CSC111 Breaking-out-of-Loop Exercises

--D. Thiebaut 09:50, 17 November 2011 (EST)

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Problem 1 (to get the idea)

• Given a list of lines L, shown below, write a program that generate the list of the line numbers for lines containing words starting with 'a' and ending with 'z'.

L = [ "------- --------- -------- --- - --------- ---------",           # line 0
       "------- ---------- a----z -------- -- --------- --------",      # line 1
       "------- ---------- ------ -------- -- --------- --------",      # line 2
       "------- ---------- ------ -------- -- --------- --------",      # line 3
       "------- ---------- ------ -------- az --------- --------",      # line 4
       "------- ---------- ------ -------- -- --------- --------" ]     # line 5

• For the example above, the result would be a list newL = [ 1, 4 ].

The enumerate function

• Here's a way to go through the items of a list and get their index at the same time:

   farm = [ "pig", "dog", "cat", "mouse", "horse" ]
   for i, animal in enumerate( farm ):
        print( "Animal #%d is a %s" % ( i, animal ) )

• Its output is the following:

Animal #0 is a pig
Animal #1 is a dog
Animal #2 is a cat
Animal #3 is a mouse
Animal #4 is a horse

Problem 2 (the real problem)

• Same idea, but we want to get the first line that contains such a word.