CODEWITHSUNDEEP
pythonloops
user977069
user977069

Reputation: 47

while loop printing list in python

The following code:

c=0 while c < len(demolist):
    print ’demolist[’,c,’]=’,demolist[c] 
    c=c+1

Creates this output:

demolist[ 0 ]= life
demolist[ 1 ]= 42
demolist[ 2 ]= the universe
demolist[ 3 ]= 6
demolist[ 4 ]= and
demolist[ 5 ]= 7
demolist[ 6 ]= everything

What's up with the demolist[',c,'] format that is being printed in the while loop? Why does this give a number in the brackets, whereas putting demolist[c] there just prints that exactly?

Upvotes: 1

Views: 11638

Answers (3)

Rob Cowie
Rob Cowie

Reputation: 22619

c is an integer. demolist[c] returns the value at index c from the list, demolist.

print ’demolist[’,c,’]=’ prints the series of objects, with an implicit conversion to a string (which is why you don't need to explicitly convert c (an integer) to a string).

A better way of writing this code is 

for idx, item in enumerate(demolist):
    print 'demolist[%d] = %s' % (idx, item)

Upvotes: 1

Mark Byers
Mark Byers

Reputation: 837946

The print statement receives four arguments (separated by commas):

’demolist[’   # string
c             # integer
’]=’          # string
demolist[c]   # result of list access

A clearer way to write that line is:

print 'demolist[ {0} ]= {1}'.format(c, demolist[c])

See it working on line: ideone

Note: You may also want to consider using enumerate here instead of a while loop.

for n, elem in enumerate(demolist):
    print 'demolist[ {0} ]= {1}'.format(n, elem)

See it working on line: ideone

Upvotes: 5

Vlad
Vlad

Reputation: 18633

print ’demolist[’,c,’]=’,demolist[c] prints the string "demolist[", the value of c, the string "]=", and the value of demolist[c], separated by spaces.

Upvotes: 2

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