Python Forum

Let's say that I have

li = ['A1','B','A2','C']

How would I go about coding a while loop that runs while li contains 'A'?

check itertools.takewhile()

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On second reading, can you elaborate what you mean exactly... i.e. in your example what is expected behaviour?

So if I have

li = ['A','B','A','C']
while 'A' in li: 
    print(li.pop(0))

It should print A B A C.

But if I have

li = ['A1','B','A2','C']
while 'A' in li: 
    print(li.pop(0))

Nothing prints. But what I want it to do is check if a substring of one of the elements contains 'A', such as in 'A1'.

First of all, your first snippet will not print A B A C, but just A B A (each on separate line)
Next, you need to change second snippet to

li = ['A1','B','A2','C']
while any('A' in item for item in li): 
    print(li.pop(0))

Output:
A1
B
A2

Finally, use collections.deque for memory efficient pop from either end.

from collections import deque
de = deque(['A1','B','A2','C'])
while any('A' in item for item in de): 
    print(de.popleft())

Thanks, it works!