how do i find the number of times a word is of len n in python?

Question

I am trying to find the number of times in a list a word is equal to a set length? So for the example: 'my name is ryan' and 2 the function would give me back 2 as the number of times a word has a length of 2. I have:

def LEN(a,b):
'str,int==>int'
'returns the number of words that have a len of b'
c=a.split()
res=0
for i in c:
    if len(i)==b:
        res=res+1
        return(res)

But all this gives me is a res of 1 and doesn't go past the first i with a len of c.

score 4 · Answer 1 · edited May 23 '17 at 12:19

4

You return res inside the for loop, and the program will immediately stop execution once it hits that statement. You can either move it outside the loop, or use this perhaps more pythonic approach:

>>> text = 'my name is ryan'
>>> sum(1 for i in text.split() if len(i) == 2)
2

Or shorter ~~but a little less clear~~ (~~but~~ and recommended):

>>> sum(len(i) == 2 for i in text.split())
2

The second function is based on that fact that True == 1

edited May 23 '17 at 12:19

Community

1
1

answered Apr 21 '13 at 03:12

Volatility

31,232
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I dont know how i didnt see that. Thanks. – blandman1990 Apr 21 '13 at 03:17
@Volatility You say the second one is less clear, I suggest you read this: http://stackoverflow.com/a/3175293/1219006 – jamylak Apr 21 '13 at 03:20
@Volatility I was hoping that would convince you it's clear :) – jamylak Apr 21 '13 at 03:30
@Volatility Yes :) Although I'm not sure why your answer was unaccepted – jamylak Apr 21 '13 at 03:36

score 3 · Accepted Answer · answered Apr 21 '13 at 03:11

Your function works fine, you are just returning early:

def LEN(a,b):
        'str,int==>int'
        'returns the number of words that have a len of b'
        c= a.split()
        res = 0
        for i in c:
            if len(i)==b:
                res= res + 1
        return(res) # return at the end

This is equivalent to:

>>> text = 'my name is ryan'
>>> sum(len(w) == 2 for w in text.split())
2

score 2 · Answer 3 · answered Apr 21 '13 at 03:13

2

How about:

>>> s = 'my name is ryan'
>>> map(len, s.split()).count(2)
2

answered Apr 21 '13 at 03:13

arshajii

127,459
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+1 for creativity `;)`. I've never seen this approach before. – Volatility Apr 21 '13 at 03:14
note: to have this work in py3k you have to use `list(map(...)).count`. In Python 3, you could do: `sum(map((2).__eq__, s.split()))` but that's pretty unclear – jamylak Apr 21 '13 at 03:14
@jamylak you mean `sum(map((2).__eq__, map(len, s.split())))`? `;)` – Volatility Apr 21 '13 at 03:20

how do i find the number of times a word is of len n in python?

3 Answers3

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