Difference between revisions of "CSC111 Lab 1 2015"

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----
 
----
  
--[[User:Thiebaut|D. Thiebaut]] ([[User talk:Thiebaut|talk]]) 10:39, 28 January 2014 (EST)
 
[[Image:PythonLogo.jpg|100px|right]]
 
 
__TOC__
 
__TOC__
 
<center>
 
<center>
Line 12: Line 10:
 
<br />
 
<br />
 
<bluebox>
 
<bluebox>
This lab is just an introduction to having fun with Python.  It's purpose is to have you explore the different systems that are available to you, and get a sense of how to program in an "intuitive" fashion.
+
This lab is just an introduction to having fun with Python.  It's purpose is to have you explore the different systems that are available to you, and get a sense of how to program in an "intuitive" fashion.  Do not worry about the details.  We haven't had time to fully understand what variables are, what strings are, or how the function print works.  Today is just a day for you to explore the tools, rund some Python code in Idle, and submit a program on Moodle.
 
</bluebox>
 
</bluebox>
 
<br />
 
<br />
Line 35: Line 33:
 
<br />
 
<br />
  
==Idle==
+
=A Quick Video Overview=
 +
<br />
 +
Here's a quick overview of how to use Idle to program in Python.  You will notice that there are two distinct ways of typing in Python statements.  The left window, in the video, is the ''console'', where each line you type is interpreted by Python.  The window on the right, however, allows you to write a collection of statements (a program), store the collection in a file, and then have Python execute the contents of the program.
 +
<br />
 +
<center><videoflash>orQp64wnRfQ</videoflash></center>
 +
<br />
 +
=Editing Programs with the ''Idle'' Editor=
 
<br />
 
<br />
 
* '''Idle''' is the name of an ''editor'' one can use to create Python program on the computer.
 
* '''Idle''' is the name of an ''editor'' one can use to create Python program on the computer.
Line 53: Line 57:
 
<br />
 
<br />
 
* Enter the following code in the '''Untitled''' window:
 
* Enter the following code in the '''Untitled''' window:
 
+
<br />
 +
<source lang="python">
 
  age = 20
 
  age = 20
 
  year = 2015
 
  year = 2015
Line 60: Line 65:
 
  print( year )
 
  print( year )
 
  print( year - age )
 
  print( year - age )
 
+
</source>
* Press '''F5''' to run the program.  When prompted to save the program, save it as '''lab1.py'''
+
<br />
 +
* Press '''F5''' to run the program.  When prompted to save the program, save it as '''lab1.py''', and save it in a folder where you can easily retrieve it (you will need to submit this file for evaluation at the end of the lab).
 
* Look at the ''Console'' window.  Some numbers appear...  Do they make sense?
 
* Look at the ''Console'' window.  Some numbers appear...  Do they make sense?
 
* change the numbers that are ''assigned'' to ''age'', and ''year'' and see how your program reacts when you run it.
 
* change the numbers that are ''assigned'' to ''age'', and ''year'' and see how your program reacts when you run it.
Line 73: Line 79:
 
<br />
 
<br />
 
* Modify your program slightly, as shown below:
 
* Modify your program slightly, as shown below:
 +
<br />
 +
<source lang="python">
 
   
 
   
 
  age = 20
 
  age = 20
Line 79: Line 87:
 
  print( age,  year )
 
  print( age,  year )
  
 +
</source>
 +
<br />
 
* Run your program
 
* Run your program
 
* Notice the slightly different output.
 
* Notice the slightly different output.
Line 85: Line 95:
 
<br />
 
<br />
 
* Try this:
 
* Try this:
+
<br />
 +
<source lang="python">
 +
 
 
  age = 20
 
  age = 20
 
  year = 2015
 
  year = 2015
Line 92: Line 104:
 
  print( "you are", age )
 
  print( "you are", age )
 
  print( "you were born in", yearBorn )
 
  print( "you were born in", yearBorn )
+
</source>
 +
<br />
 
* Run your program.  Change the year and the age.  Run your program again and see if you can predict the output.
 
* Run your program.  Change the year and the age.  Run your program again and see if you can predict the output.
 
<br />
 
<br />
Line 98: Line 111:
 
<br />
 
<br />
 
* This time we add new variables that contain text.  In computer science we refer to text as ''strings of characters'', or ''strings'' for short.
 
* This time we add new variables that contain text.  In computer science we refer to text as ''strings of characters'', or ''strings'' for short.
+
<br />
 +
<source lang="python">
 +
 
 
  name = "Alex"
 
  name = "Alex"
 
  college = "Smith College"
 
  college = "Smith College"
Line 106: Line 121:
 
  print( name, "goes to", college )
 
  print( name, "goes to", college )
 
  print( name, "is", age, "years old" )
 
  print( name, "is", age, "years old" )
+
</source>
* Run your program a few times, each time changing some of the variables.
+
<br />
 
+
* Run your program a few times, each time changing the value of a variableFor example change "Alex" to "Monique", or year to 2015.
===Using ''Strings'' of characters===
 
<br />
 
* Modify the ''print statement'' so that it reads like this:
 
 
 
print( "You are", age, "years old and you were born in", year - age )
 
 
 
* Run your new programDo you understand how your modification made the program run differently?  Does the output still make sense?  Don't worry too much for today if it doesn't.  Be sure to ask questions to your instructor or to the TAs if you're unsure about anything.
 
 
 
* Another modification.  Replace your print statement by two statements:
 
 
 
print( "You are", age, "years old" )
 
print( "You were born in", year - age )
 
 
 
* Run your program again.   How does having a second print statement modify the behavior of your program?
 
  
  
Line 132: Line 133:
 
|}
 
|}
 
[[Image:QuestionMark1.jpg|right|120px]]
 
[[Image:QuestionMark1.jpg|right|120px]]
* Now, use your intuition along with what you have just learned, and modify your program to make it display this output:
+
* Write a new program that contains these variables:
 
+
   
a = 3
 
b = 10
 
  c = 20
 
sum = 33
 
 
 
* Keep at it if you don't get there right away.  Remember, this is a language, and there exist many different ways to say the same thing in Python...
 
<br />
 
<br />
 
 
<br />
 
<br />
 +
<source lang="python">
  
===Playing with Strings===
+
  name = "Alex"
<br />
 
* The goal of this section if for you to modify your program, play with different ''Python statements,'' and start building an intuition for how Python statements work.
 
 
 
* Type  the following three lines of code in your program (you can keep the old lines and add new lines at the end, or you can erase everything and type the new ones), and run the program.
 
 
 
word1 = "Hello"
 
  word2 = "world"
 
 
  college = "Smith College"
 
  college = "Smith College"
  print( word1, word2 )
+
  age = 20
  print( word1, college )
+
  year = 2015
print( college )
 
  
* Observe how the different ways to write the print statements influence how the information is printed.
+
</source>
 +
<br />
 +
* Figure out how to add new variables and write several '''print''' statements that will make your program output:
  
* Now, try these lines of code:
+
Alex goes to Smith College and is 20 years old
 +
Alex was born in 1995
  
word1 = "hello"
 
word2 = "there!"
 
print( word1, word2 )
 
print( word1, "who is", word2 )
 
  
 +
* If your program is well written, and if you change the variable ''name'' to be "Francis", college to be "Umass", and age to be 18, then your program should automatically output:
 +
 +
Francis goes to Umass and is 18 years old
 +
Francis was born in 1997
 +
 +
* Verify that your program works correctly
 
<br />
 
<br />
 
<br />
 
<br />
 
<br />
 
<br />
:'''Question:'''  What is the role of ''word1'' or ''word2'' in the program?
 
<br />
 
<br />
 
<br />
 
:'''Question:''' What is the role of the double quote character in Python?
 
<br />
 
<br />
 
<br />
 
{| style="width:100%; background:silver"
 
|-
 
|
 
  
===Challenge #2===
+
===Repeating Strings===
|}
 
[[Image:QuestionMark2.jpg|right|100px]]
 
  
* Modify your program but keep the two ''variables'' '''word1''' and '''word2''', and make it print this:
+
* Write a new program:
   
 
  hello there!
 
  there! hello
 
  hello hello hello
 
  hello there! there! hello
 
 
<br />
 
<br />
 +
<source lang="python">
 +
 +
word1 = "hello"
 +
word2 = "there "
 +
 
 +
print( word1 * 2 )
 +
print( word1 * 5 )
 +
print( word2 * 10 )
 +
</source>
 
<br />
 
<br />
 +
* See how you can ''multiply'' a string?
 
<br />
 
<br />
 
===Repeating Strings===
 
 
 
* Try this:
 
* Try this:
 +
<br />
 +
<source lang="python">
  
  word1 = "hello"
+
  print( word1 * 2, word2 * 4 )
  
print( word1 * 2 )
+
</source >
print( word1 * 5 )
 
print( word1 * 10 )
 
 
 
* See how you can ''multiply'' a string?
 
 
<br />
 
<br />
 +
* Run the program.  Does the output make sense?
 
<br />
 
<br />
 
<br />
 
<br />
Line 213: Line 192:
 
|-
 
|-
 
|
 
|
===Challenge #3===
+
 
 +
===Challenge #2===
 
|}
 
|}
 
[[Image:QuestionMark3.jpg|right|110px]]
 
[[Image:QuestionMark3.jpg|right|110px]]
  
* Modify your program and make it print this:
+
* Modify your program (you are allowed to change the contents of the variables), and make it print the output shown below. Note the new exclamation point:
  
  hello hello hello hello there!  
+
  hello hello hello hello&nbsp;&nbsp;there!
 
  hello there! there! there! there! there! hello
 
  hello there! there! there! there! there! hello
 
<br />
 
<br />
Line 228: Line 208:
 
|-
 
|-
 
|
 
|
===Challenge #4 (tricky)===
+
 
 +
===Challenge #3 (tricky)===
 
|}
 
|}
 
[[Image:QuestionMark4.jpg|right|100px]]
 
[[Image:QuestionMark4.jpg|right|100px]]
* See if you can make your program print this, using string multiplication:
+
* Make your program print the output below, using a string and the string multiplication operation:
  
 
  hellothere!hellothere!hellothere!hellothere!hellothere!
 
  hellothere!hellothere!hellothere!hellothere!hellothere!
Line 239: Line 220:
 
<br />
 
<br />
 
<br />
 
<br />
 
  
 
===Playing with Lists and Loops===
 
===Playing with Lists and Loops===
Line 247: Line 227:
 
<br />
 
<br />
 
<source lang="python">
 
<source lang="python">
  list = [ "Lea Jones", "Julie Fleur", "Anu Vias" ]
+
 
for name in list:
+
  for name in [ "Lea Jones", "Julie Fleur", "Anu Vias" ]:
 
     print( name )
 
     print( name )
 +
 
</source>
 
</source>
 
<br />
 
<br />
 
<br />
 
<br />
  
<tanbox>Observe that the line that starts with ''print'' is indented from the line that starts with ''for''.  This is a '''very important''' detail: Python uses ''indentation'' to influence how statements depend on each other.
+
<tanbox>Observe that the line that starts with ''print'' is indented from the line that starts with ''for''.  This is a '''very important''' detail: Python uses ''indentation'' to influence how statements depend on each other.  Because the '''print''' statement is indented relative to the '''for''' statement, it is ''controlled'' by the '''for''' statement, and will be repeated for each string in the list.
 
</tanbox>
 
</tanbox>
 
<br />
 
<br />
Line 267: Line 248:
 
|
 
|
  
===Challenge #5===
+
===Challenge #4===
 
|}
 
|}
 
[[Image:QuestionMark5.jpg|right|100px]]
 
[[Image:QuestionMark5.jpg|right|100px]]
Line 274: Line 255:
  
  
 +
<br />
 +
<br />
 +
<br />
 
<br />
 
<br />
 
<br />
 
<br />
Line 279: Line 263:
  
 
===Repeating several statements===
 
===Repeating several statements===
* Play with these different code segments, each one on its own.  Make sure you understand how each one works when you execute the program.
+
* Play with these different code snippets.  Make sure you understand how your program works before moving on to the next sections. 
 +
<br />
 +
<tanbox>
 +
The purpose is not to go quickly through the lab, but to start acquiring an intuition for the logic of programming.
 +
</tanbox>
  
 
<br />
 
<br />
 
<br />
 
<br />
 
<source lang="python">
 
<source lang="python">
  list = [ "Lea Jones", "Julie Fleur", "Anu Vias" ]
+
 
for name in list:
+
  for name in [ "Lea Jones", "Julie Fleur", "Anu Vias" ]:
 
     print( name )
 
     print( name )
     print( "-" )
+
     print( "---------------" )
 +
 
 
</source>
 
</source>
 
<br />
 
<br />
Line 296: Line 285:
 
<br />
 
<br />
 
<source lang="python">
 
<source lang="python">
  list = [ "Lea Jones", "Julie Fleur", "Anu Vias" ]
+
  for name in [ "Lea Jones", "Julie Fleur", "Anu Vias" ]:
for name in list:
 
 
     print( name, len( name ) )
 
     print( name, len( name ) )
 
</source>
 
</source>
Line 307: Line 295:
 
<br />
 
<br />
 
<source lang="python">
 
<source lang="python">
  list = [ "Lea Jones", "Julie Fleur", "Anu Vias" ]
+
 
for name in list:
+
for name in [ "Lea Jones", "Julie Fleur", "Anu Vias" ]:
 
     print( name )
 
     print( name )
 
     print ( len( name ) )
 
     print ( len( name ) )
Line 320: Line 308:
 
<br />
 
<br />
 
<source lang="python">
 
<source lang="python">
  list = [ "Lea Jones", "Julie Fleur", "Anu Vias" ]
+
 
for name in list:
+
  for name in [ "Lea Jones", "Julie Fleur", "Anu Vias" ]:
 
     print( name,  '-'  * len( name ) )
 
     print( name,  '-'  * len( name ) )
 
</source>
 
</source>
Line 332: Line 320:
 
|-
 
|-
 
|
 
|
===Challenge #6===
+
 
 +
===Challenge #5===
 
|}
 
|}
 
[[Image:QuestionMark6.jpg|right|100px]]
 
[[Image:QuestionMark6.jpg|right|100px]]
* Make your program display the names with a bar made of minus signs under each name.  The length of the bar should be the same as the length of the name.  For example:
+
* Make your program display the names with a bar made of minus signs under each name.  The length of the bar should be the same as the length of the name that is above it.  For example:
  
 
  Lea Jones
 
  Lea Jones
Line 351: Line 340:
 
|-
 
|-
 
|
 
|
===Challenge #7===
+
 
 +
===Challenge #6===
 
|}
 
|}
 
[[Image:QuestionMark7.png|right|100px]]
 
[[Image:QuestionMark7.png|right|100px]]
Line 375: Line 365:
 
|-
 
|-
 
|
 
|
 +
 
===Challenge of the Day===
 
===Challenge of the Day===
 
|}
 
|}
 
[[Image:QuestionMark8.jpg|right|150px]]
 
[[Image:QuestionMark8.jpg|right|150px]]
  
* Make your program display a box around each name:
+
====Step 1====
 +
<br />
 +
* Create a program with all the statements below.  They contain the solution for this challenge.  You will need to figure out how to reorganize them and modify them to create the answer for this challenge.  So create this program and study carefully its code and its output.
 +
<br />
 +
<source lang="python">
 +
name = "Julia Child"
 +
nameLen = len( name )
 +
nameLen4 = len( name ) + 4
 +
nameLen2 = len( name ) + 2
 +
x = 10
 +
bar1 = "-" * x
 +
bar2 = bar1 + "|"
 +
bar3 = "<" + bar1 + ">"
 +
bar4 = "-" * nameLen
 +
 
 +
print( "name = ", name )
 +
print( "nameLen = ", nameLen )
 +
print( "nameLen4 = ", nameLen4 )
 +
print( "nameLen2 = ", nameLen2 )
 +
print( "x = ", x )
 +
print( "bar1 = ", bar1 )
 +
print( "bar2 = ", bar2 )
 +
print( "bar3 = ", bar3 )
 +
print( "bar4 = ", bar4 )
 +
 
 +
</source>
 +
<br />
 +
* Change "Julia Child" for some other, longer, name.  Run your program again and see how the different variables will change according to the length of the string you store in ''name''.
 +
<br />
 +
====Step 2====
 +
<br />
 +
* Modify your program as follows:
 +
<br />
 +
<source lang="python">
 +
for name in [ "Julia Child", "Gloria Steinem" ]:
 +
    nameLen = len( name )
 +
    nameLen4 = len( name ) + 4
 +
    nameLen2 = len( name ) + 2
 +
    x = 10
 +
    bar1 = "-" * x
 +
    bar2 = bar1 + "|"
 +
    bar3 = "<" + bar1 + ">"
 +
    bar4 = "-" * nameLen
 +
 
 +
    print( "nameLen = ", nameLen )
 +
    print( "nameLen4 = ", nameLen4 )
 +
    print( "nameLen2 = ", nameLen2 )
 +
    print( "x = ", x )
 +
    print( "name = ", name )
 +
    print( "bar1 = ", bar1 )
 +
    print( "bar2 = ", bar2 )
 +
    print( "bar3 = ", bar3 )
 +
    print( "bar4 = ", bar4 )
 +
    print()
 +
</source>
 +
<br />
 +
 
 +
* Carefully look at the output of your program.  Because all the '''print''' statements are indented relative to the '''for''' statement, they are repeated for every name in the list.  See how bar1 and bar2 do not change in length, but bar4 changes with each string.
 +
<br />
 +
* Here is your challenge for today: Make your program use a for-statement and a list of 3 names, and make it display a box around each name.  The challenge here is that the box must fit exactly the length of the name, without extra spaces around.
  
 
  -------------
 
  -------------
Line 398: Line 448:
 
<br />
 
<br />
  
* And... if you are done, and are really rolling and want some more of a challenge, try to make your program output this:
+
=Submission of Lab 1 Program on Moodle=
 +
<br />
 +
* For this lab you need to submit your solution program on Moodle. This submission is graded and the grade counts toward your lab grade for this class (15% of the total grade). 
 +
* Go to this [[CSC111 Submitting Programs to Moodle 2015| page]] and follow the directions for submitting your program.
 +
<br />
 +
* '''Deadline''': Exceptionally, this week, the deadline is set to 2/6/05, to allow Add/Drop students to catch up.
 +
* '''Grade''':
 +
** Program submitted with syntax errors: '''90/100'''
 +
** Program submitted without errors, but incorrect output: '''95/100'''
 +
** Program submitted ''with correct output'': '''100/100'''
 +
<br />
 +
<br />
 +
 
 +
{| style="width:100%; background:silver"
 +
|-
 +
|
 +
 
 +
= Optional Challenge =
 +
|}
 +
[[Image:QuestionMark8.jpg|right|150px]]
 +
* This is not required today, but if you want some extra challenging coding to do, try making your program generate the output below.
  
 
  +-----------+
 
  +-----------+
Line 415: Line 485:
 
<br />
 
<br />
 
<br />
 
<br />
 +
* You do not have to submit this program. 
 +
 +
 +
<br />
 +
<br />
 +
<showafterdate after="20150207 00:00" before="20150601 00:00">
 +
<br />
 +
=Solution Programs=
 +
<br />
 +
<source lang="python">
 +
# CSC111 Lab1
 +
# D. Thiebaut
 +
# solution programs for Lab1
 +
 +
 +
# Challenge #1
 +
name = "Alex"
 +
college = "Smith College"
 +
age = 20
 +
year = 2015
 +
 +
print( name, "goes to", college, "and is", age, "years old" )
 +
print( name, "was born in", year - age )
 +
print()
 +
 +
# Challenge #2
 +
word1 = "hello "
 +
word2 = "there! "
 +
 +
print( word1 * 4, word2 )
 +
print( word1, word2*5, word1 )
 +
print()
 +
 +
# Challenge #3
 +
word1 = "hello"
 +
word2 = "there!"
 +
word3 = word1 + word2
 +
print( word3*5 )
 +
print( ("hello" + "there!") * 5 )
 +
print()
 +
 +
# Challenge #4
 +
for name in [ "Lea Jones", "Julie Fleur", "Anu Vias",
 +
              "Mickey", "Minnie", "Pluto" ]:
 +
    print( name )
 +
 +
print()
 +
 +
# Challenge #5
 +
for name in [ "Lea Jones", "Julie Fleur", "Anu Vias",
 +
              "Mickey", "Minnie", "Pluto" ]:
 +
    print( name )
 +
    print( "-" * len( name ) )
 +
 +
print()
  
 +
# Challenge #6
 +
for name in [ "Lea Jones", "Julie Fleur", "Anu Vias",
 +
              "Mickey", "Minnie", "Pluto" ]:
 +
    print( "-" * len( name ) )
 +
    print( name )
 +
    print( "-" * len( name ) )
 +
   
 +
print()
  
 +
# Challenge #7
 +
for name in [ "Lea Jones", "Julie Fleur", "Anu Vias",
 +
              "Mickey", "Minnie", "Pluto" ]:
 +
    name2 = "| " + name + " |"
 +
    bar = "-" * len( name2 )
 +
    print( bar )
 +
    print( name2 )
 +
    print( bar )
 +
    print()
  
 +
print()
 +
 +
# Optional Challenge
 +
for name in [ "Lea Jones", "Julie Fleur", "Anu Vias",
 +
              "Mickey", "Minnie", "Pluto" ]:
 +
    name2 = "| " + name + " |"
 +
    bar = "-" * len( name )
 +
    bar = "+-" + bar + "-+"
 +
    print( bar )
 +
    print( name2 )
 +
    print( bar )
 +
    print()
 +
 +
print()
 +
 +
 +
</source>
 +
<br />
 +
</showafterdate>
 
<br />
 
<br />
 +
<onlydft>
 +
=VPL Module=
 
<br />
 
<br />
 +
<source lang="text">
 +
vpl_run.sh
 +
    1 #! /bin/bash
 +
    2
 +
    3 cat > vpl_execution <<EOF
 +
    4 #! /bin/bash
 +
    5
 +
    6 prog=lab1.py
 +
    7 python=/usr/local/bin/python3.4
 +
    8
 +
    9 \$python \$prog
 +
  10
 +
  11 EOF
 +
  12
 +
  13 chmod +x vpl_execution
 +
vpl_debug.sh
 +
vpl_evaluate.sh
 +
    1 #! /bin/bash
 +
    2
 +
    3 cat > vpl_execution <<EOF
 +
    4 #! /bin/bash
 +
    5
 +
    6 prog=lab1.py
 +
    7 python=/usr/local/bin/python3.4
 +
    8 #python=/usr/bin/python3.3
 +
    9
 +
  10 #--- grab program errors ---
 +
  11 \$python \$prog 2>&1 >/dev/null | grep -B 10 -i "error" > error.out
 +
  12
 +
  13 if [ -s error.out ] ; then
 +
  14    echo "Comment :=>> Your program contains some errors:"
 +
  15    echo "<|--"                                                                                 
 +
  16    cat error.out                                                                               
 +
  17    echo "--|>"
 +
  18    echo "Grade :=>> 90"
 +
  19    exit
 +
  20 fi
 +
  21
 +
  22 #--- ensure that the program contains a for loop ---
 +
  23 grep "^for" lab1.py > grepLines.out
 +
  24
 +
  25 if [ -s grepLines.out ] ; then
 +
  26    rm grepLines.out
 +
  27 else
 +
  28    echo "Comment :=>> Your program does not use a for loop."
 +
  29    echo "Grade :=>> 95"
 +
  30    exit
 +
  31 fi
 +
  32
 +
  33 # create expected output
 +
  34 cat > expected1.out <<EOFEOF
 +
  35 -------------
 +
  36 | Lea Jones |
 +
  37 -------------
 +
  38 ---------------
 +
  39 | Julie Fleur |
 +
  40 ---------------
 +
  41 ------------
 +
  42 | Anu Vias |
 +
  43 ------------
 +
  44 EOFEOF
 +
  45
 +
  46 #--- capture output of program
 +
  47 \$python \$prog > user1.out
 +
  48
 +
  49 #--- remove blank lines ---
 +
  50 cat user1.out | sed '/^\s*$/d' > dummy.out
 +
  51 mv dummy.out user1.out
 +
  52
 +
  53 #--- add space in front of each line ---
 +
  54 sed 's/^/ /' user1.out
 +
  55
 +
  56 #--- compute difference ---
 +
  57 diff -y -w  user1.out expected1.out > diff.out
 +
  58
 +
  59 #--- reject if different ---
 +
  60 if ((\$? > 0)); then
 +
  61      echo "Comment :=>>- Your output is incorrect."
 +
  62
 +
  63      echo "Comment :=>> ---------------"
 +
  64      echo "Comment :=>>- Your output:"
 +
  65      echo "Comment :=>> ---------------"
 +
  66      echo "<|--"
 +
  67      cat user1.out
 +
  68      echo "--|>"
 +
  69      echo ""
 +
  70      echo "Comment :=>> ---------------"
 +
  71      echo "Comment :=>>- Expected output:"
 +
  72      echo "Comment :=>> ---------------"
 +
  73      echo "<|--"
 +
  74      cat expected1.out
 +
  75      echo "--|>"
 +
  76   
 +
  77      #--- consolation grade --- 
 +
  78      grade=95
 +
  79
 +
  80      # --------------------- REWARD IF CORRECT OUTPUT -----------------
 +
  81    else
 +
  82      #--- good output ---
 +
  83      echo "Comment :=>>- Congrats, your output is correct."
 +
  84      echo "Comment :=>> --------------------------------."
 +
  85      echo "<|--"
 +
  86      cat user1.out
 +
  87      echo "--|>"
 +
  88      grade=100
 +
  89 fi
 +
  90
 +
  91 #--- round down to 100 ---
 +
  92 if (( grade > 100 )); then
 +
  93      grade=100
 +
  94 fi
 +
  95
 +
  96 #--- output final grade ---
 +
  97 echo "Grade :=>> \$grade"
 +
  98 EOF
 +
  99
 +
  100 chmod +x vpl_execution
 +
  101 
 +
</source>
 
<br />
 
<br />
 +
</onlydft>
 
<br />
 
<br />
 
<br />
 
<br />

Latest revision as of 15:33, 7 September 2015

--D. Thiebaut (talk) 16:21, 19 January 2015 (EST)



FUN WITH PYTHON



This lab is just an introduction to having fun with Python. It's purpose is to have you explore the different systems that are available to you, and get a sense of how to program in an "intuitive" fashion. Do not worry about the details. We haven't had time to fully understand what variables are, what strings are, or how the function print works. Today is just a day for you to explore the tools, rund some Python code in Idle, and submit a program on Moodle.



Option 1: Installing and Running Python on your Laptop

  • If you want to work on your own laptop, you need to install Python 3. Open this page and follow the instructions for downloading Python 3 to your laptop.


Option 2: Using Python on a Lab Computer


  • If your computer is not on, turn it ON, please!
  • When prompted for booting Mac or Windows, select the Mac if you have the choice.
  • Login using the Smith credentials (or the account that was given to you as a 5-college or high school student)
  • Once you see the Desktop, click on the Finder (bottom left icon on the Desktop), and look in the Science Apps folder for Python 3.2.
  • Start IDLE


Tip: if you can't find Idle, use the magnifying glass icon at the top right of the screen and search for idle and you should find it!


A Quick Video Overview


Here's a quick overview of how to use Idle to program in Python. You will notice that there are two distinct ways of typing in Python statements. The left window, in the video, is the console, where each line you type is interpreted by Python. The window on the right, however, allows you to write a collection of statements (a program), store the collection in a file, and then have Python execute the contents of the program.


Editing Programs with the Idle Editor


  • Idle is the name of an editor one can use to create Python program on the computer.
  • If the window you start with looks like this (see below), then use the top menu and click File, New Window to open an editing window.

CSC111 PythonShell.png


  • You should now have two windows on your screen, one the editing window, the other the shell window, where the program will send its output.

CSC111 PythonEditShellWindows.png


Some Python Code to play with


Playing with numbers


  • Enter the following code in the Untitled window:


 age = 20
 year = 2015
 
 print( age )
 print( year )
 print( year - age )


  • Press F5 to run the program. When prompted to save the program, save it as lab1.py, and save it in a folder where you can easily retrieve it (you will need to submit this file for evaluation at the end of the lab).
  • Look at the Console window. Some numbers appear... Do they make sense?
  • change the numbers that are assigned to age, and year and see how your program reacts when you run it.


age, and year are variables. You can give variables any name you want, as long as you use letters or digits, and as long as the first character is a letter. R2d2 is a valid name for a variable. And so is alpha, or c3po. Variables are used to hold information, in our case, numbers.


Variation 1


  • Modify your program slightly, as shown below:


 
 age = 20
 year = 2015
 
 print( age,  year )


  • Run your program
  • Notice the slightly different output.


Variation 2


  • Try this:


 age = 20
 year = 2015
 yearBorn = year - age
 
 print( "you are", age )
 print( "you were born in", yearBorn )


  • Run your program. Change the year and the age. Run your program again and see if you can predict the output.


Playing with Numbers and Strings


  • This time we add new variables that contain text. In computer science we refer to text as strings of characters, or strings for short.


 name = "Alex"
 college = "Smith College"
 age = 20
 year = 2015
 
 print( name, "goes to", college )
 print( name, "is", age, "years old" )


  • Run your program a few times, each time changing the value of a variable. For example change "Alex" to "Monique", or year to 2015.


Challenge #1

QuestionMark1.jpg
  • Write a new program that contains these variables:


 name = "Alex"
 college = "Smith College"
 age = 20
 year = 2015


  • Figure out how to add new variables and write several print statements that will make your program output:
Alex goes to Smith College and is 20 years old
Alex was born in 1995


  • If your program is well written, and if you change the variable name to be "Francis", college to be "Umass", and age to be 18, then your program should automatically output:
Francis goes to Umass and is 18 years old
Francis was born in 1997

  • Verify that your program works correctly




Repeating Strings

  • Write a new program:


word1 = "hello"
word2 = "there "
  
print( word1 * 2 )
print( word1 * 5 )
print( word2 * 10 )


  • See how you can multiply a string?


  • Try this:


 print( word1 * 2, word2 * 4 )


  • Run the program. Does the output make sense?



Challenge #2

QuestionMark3.jpg
  • Modify your program (you are allowed to change the contents of the variables), and make it print the output shown below. Note the new exclamation point:
hello hello hello hello  there!  
hello there! there! there! there! there! hello




Challenge #3 (tricky)

QuestionMark4.jpg
  • Make your program print the output below, using a string and the string multiplication operation:
hellothere!hellothere!hellothere!hellothere!hellothere!





Playing with Lists and Loops

  • Create a new program in Idle with this new piece of code:



   
 for name in [ "Lea Jones", "Julie Fleur", "Anu Vias" ]:
     print( name )



Observe that the line that starts with print is indented from the line that starts with for. This is a very important detail: Python uses indentation to influence how statements depend on each other. Because the print statement is indented relative to the for statement, it is controlled by the for statement, and will be repeated for each string in the list.


  • Press F5. Observe the output.




Challenge #4

QuestionMark5.jpg
  • Add three new names to the list and make your program output them all one above the other.








Repeating several statements

  • Play with these different code snippets. Make sure you understand how your program works before moving on to the next sections.


The purpose is not to go quickly through the lab, but to start acquiring an intuition for the logic of programming.



 for name in [ "Lea Jones", "Julie Fleur", "Anu Vias" ]:
     print( name )
     print( "---------------" )



  • and this one:



 for name in [ "Lea Jones", "Julie Fleur", "Anu Vias" ]:
     print( name, len( name ) )



  • or:



 for name in  [ "Lea Jones", "Julie Fleur", "Anu Vias" ]:
     print( name )
     print ( len( name ) )



  • Still some more



 for name in [ "Lea Jones", "Julie Fleur", "Anu Vias" ]:
     print( name,  '-'  * len( name ) )




Challenge #5

QuestionMark6.jpg
  • Make your program display the names with a bar made of minus signs under each name. The length of the bar should be the same as the length of the name that is above it. For example:
Lea Jones
---------
Julie Fleur
-----------
Anu Vias
--------




Challenge #6

QuestionMark7.png
  • Similar question, but now like this:
---------
Lea Jones
---------

-----------
Julie Fleur
-----------

--------
Anu Vias
--------




Challenge of the Day

QuestionMark8.jpg

Step 1


  • Create a program with all the statements below. They contain the solution for this challenge. You will need to figure out how to reorganize them and modify them to create the answer for this challenge. So create this program and study carefully its code and its output.


name = "Julia Child"
nameLen = len( name )
nameLen4 = len( name ) + 4
nameLen2 = len( name ) + 2
x = 10
bar1 = "-" * x
bar2 = bar1 + "|"
bar3 = "<" + bar1 + ">"
bar4 = "-" * nameLen

print( "name = ", name )
print( "nameLen = ", nameLen )
print( "nameLen4 = ", nameLen4 )
print( "nameLen2 = ", nameLen2 )
print( "x = ", x )
print( "bar1 = ", bar1 )
print( "bar2 = ", bar2 )
print( "bar3 = ", bar3 )
print( "bar4 = ", bar4 )


  • Change "Julia Child" for some other, longer, name. Run your program again and see how the different variables will change according to the length of the string you store in name.


Step 2


  • Modify your program as follows:


for name in [ "Julia Child", "Gloria Steinem" ]:
    nameLen = len( name )
    nameLen4 = len( name ) + 4
    nameLen2 = len( name ) + 2
    x = 10
    bar1 = "-" * x
    bar2 = bar1 + "|"
    bar3 = "<" + bar1 + ">"
    bar4 = "-" * nameLen

    print( "nameLen = ", nameLen )
    print( "nameLen4 = ", nameLen4 )
    print( "nameLen2 = ", nameLen2 )
    print( "x = ", x )
    print( "name = ", name )
    print( "bar1 = ", bar1 )
    print( "bar2 = ", bar2 )
    print( "bar3 = ", bar3 )
    print( "bar4 = ", bar4 )
    print()


  • Carefully look at the output of your program. Because all the print statements are indented relative to the for statement, they are repeated for every name in the list. See how bar1 and bar2 do not change in length, but bar4 changes with each string.


  • Here is your challenge for today: Make your program use a for-statement and a list of 3 names, and make it display a box around each name. The challenge here is that the box must fit exactly the length of the name, without extra spaces around.
-------------
| Lea Jones |
-------------

---------------
| Julie Fleur |
---------------

------------
| Anu Vias |
------------




Submission of Lab 1 Program on Moodle


  • For this lab you need to submit your solution program on Moodle. This submission is graded and the grade counts toward your lab grade for this class (15% of the total grade).
  • Go to this page and follow the directions for submitting your program.


  • Deadline: Exceptionally, this week, the deadline is set to 2/6/05, to allow Add/Drop students to catch up.
  • Grade:
    • Program submitted with syntax errors: 90/100
    • Program submitted without errors, but incorrect output: 95/100
    • Program submitted with correct output: 100/100



Optional Challenge

QuestionMark8.jpg
  • This is not required today, but if you want some extra challenging coding to do, try making your program generate the output below.
+-----------+
| Lea Jones |
+-----------+

+-------------+
| Julie Fleur |
+-------------+

+----------+
| Anu Vias |
+----------+




  • You do not have to submit this program.




<showafterdate after="20150207 00:00" before="20150601 00:00">

Solution Programs


# CSC111 Lab1
# D. Thiebaut
# solution programs for Lab1


# Challenge #1
name = "Alex"
college = "Smith College"
age = 20
year = 2015

print( name, "goes to", college, "and is", age, "years old" )
print( name, "was born in", year - age )
print()

# Challenge #2
word1 = "hello "
word2 = "there! "

print( word1 * 4, word2 )
print( word1, word2*5, word1 )
print()

# Challenge #3
word1 = "hello"
word2 = "there!"
word3 = word1 + word2
print( word3*5 )
print( ("hello" + "there!") * 5 )
print()

# Challenge #4
for name in [ "Lea Jones", "Julie Fleur", "Anu Vias",
              "Mickey", "Minnie", "Pluto" ]:
     print( name )

print()

# Challenge #5
for name in [ "Lea Jones", "Julie Fleur", "Anu Vias",
              "Mickey", "Minnie", "Pluto" ]:
     print( name )
     print( "-" * len( name ) )

print()

# Challenge #6
for name in [ "Lea Jones", "Julie Fleur", "Anu Vias",
              "Mickey", "Minnie", "Pluto" ]:
     print( "-" * len( name ) )
     print( name )
     print( "-" * len( name ) )
    
print()

# Challenge #7
for name in [ "Lea Jones", "Julie Fleur", "Anu Vias",
              "Mickey", "Minnie", "Pluto" ]:
    name2 = "| " + name + " |"
    bar = "-" * len( name2 )
    print( bar )
    print( name2 )
    print( bar )
    print()

print()

# Optional Challenge
for name in [ "Lea Jones", "Julie Fleur", "Anu Vias",
              "Mickey", "Minnie", "Pluto" ]:
    name2 = "| " + name + " |"
    bar = "-" * len( name )
    bar = "+-" + bar + "-+"
    print( bar )
    print( name2 )
    print( bar )
    print()

print()


</showafterdate>


...