CODEWITHSUNDEEP
python
user8544907
user8544907

Reputation:

python unexpected null in string.isalpha()

function should change sentence to list of words separated by space and than checks if there are 3 words in a row containing only letters

def words(str):
slowa = str.split(str)
if len(slowa) < 2:
    return 0
else:
    for x in range(2,len(slowa)):
        if slowa[x].isalpha() and slowa[x-1].isalpha() and slowa[x-2].isalpha():
            return 1
        else:
            return 0

fe: words("one one one") returns true

but words("one one 1 one one one 1 one one 1 one one 1") returns false. Any tips why this happens?

Upvotes: 0

Views: 130

Answers (1)

Martijn Pieters
Martijn Pieters

Reputation: 1123400

Because you return 0 on the first failed test in your loop. The loop exits with a return, you never tested the rest of your list. "one one 1" is not a match, you need to continue looping until you find the "one one one" sequence later on.

Move the return 0 to after the for loop, only when you have tested all positions do you know for sure there is nothing matching:

for x in range(2,len(slowa)):
    if slowa[x].isalpha() and slowa[x-1].isalpha() and slowa[x-2].isalpha():
        return 1

return 0

Note that your test for the length is redundant; the range() will simply be empty for shorter sequences:

def words(inputstring):
    slowa = inputstring.split()
    for x in range(2, len(slowa)):
        if slowa[x].isalpha() and slowa[x-1].isalpha() and slowa[x-2].isalpha():
            return 1
    return 0

Upvotes: 1

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