CSC111 Lab 9 2014

--D. Thiebaut (talk) 23:40, 1 April 2014 (EDT)

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Reading and Writing Text Files

Write Example

# write some variables to file
name = "Smith College"
address = "1 Elm st., Northampton, MA 01063"
file = open( "college.txt", "w" )
file.write( "%s\n" % name )
file.write( "%s\n" % address )
file.close()

Read Example

# read the same file back and print all the lines
file = open( "college.txt", "r" )
for line in file:
   print( "line =", line.strip() )
file.close()

Writing Information to File

Challenge 1

• Use the example above and write a program that writes the string text defined below to a file named poem.txt in the same folder (directory) where your program is located.

text = """An Evening by Gwendolyn Brooks

A sunset's mounded cloud; 
A diamond evening-star; 
Sad blue hills afar; 
Love in his shroud. 

Scarcely a tear to shed; 
Hardly a word to say; 
The end of a summer day; 
Sweet Love dead."""

• Once the program terminates, open the file with TextEdit if working on a Mac, or with Notepad if working on Windows. Verify that the file exists and that it contains the poem.

• Put the code that writes the poem to file in a function called writeText( fileName, text ), where fileName is the name of the file, and text the name of the variable. The function should 1) open the file for writing, 2) write text to the file, and 3) close the file.

Challenge 2

• Add some code to your program that will read the file just created and print its contents (all the lines) on the screen.

• When this works, put this new code into a function called readTextFile() that is given just the file name (fileName) and that returns a long string that is equal to the contents of the file. Here is an example of how your program will use your new function to read the file and display the string:

        text = readTextFile(  "poem.txt" )
        print( text )