Python Function for List of Lists

Question

I want to find the lengths of words in sentences, and return the results as a list of lists.

So something like

lucky = ['shes up all night til the sun', 'shes up all night for the fun', 'hes up all night to get some', 'hes up all night to get lucky']

should become

[[4, 2, 3, 5, 3, 3, 3], [4, 2, 3, 5, 3, 3, 3], [3, 2, 3, 5, 2, 3, 4], [3, 2, 3, 5, 2, 3, 5]]

Here's the code

result =[]

def sentancewordlen(x)
    for i in x:
        splitlist = x.split(" ")
        temp=[]
        for y in splitlist:
                l = len(y)
                temp.append(l)
        result.append(temp)
sentancewordlen(lucky)

What comes out is the results of the last sentence, with each length in its own list.

[[3], [2], [3], [5], [2], [3], [5]]

Any idea where I'm goofing up?

Apart from the fact that you call x.split instead of i.split in your loop, your code works absolutely fine and gives the right result. — Daniel Roseman
– Daniel Roseman, Commented Mar 5, 2017 at 12:55

xtofl · Accepted Answer · 2017-03-05 12:53:46Z

4

I hate thinking about these changing lists altogether. The more pythonic version is with list comprehensions:

result = [
    [len(word) for word in sentence.split(" ")]
    for sentence in sentences]

answered Mar 5, 2017 at 12:53

xtofl

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Spherical Cowboy · Accepted Answer · 2017-03-05 12:57:58Z

1

A more concise solution would be:

lengths = [[len(w) for w in s.split()] for s in lucky]

Output:

[[4, 2, 3, 5, 3, 3, 3], [4, 2, 3, 5, 3, 3, 3], [3, 2, 3, 5, 2, 3, 4], [3, 2, 3, 5, 2, 3, 5]]

Explanation:

for s in lucky will iterate through all strings in lucky. With s.split() we then split each string s into the words it is made up of. Using len(w), we then obtain the length (number of characters) for each word w in s.split().

answered Mar 5, 2017 at 12:57

Spherical Cowboy

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Community · Accepted Answer · 2017-05-23 11:46:07Z

0

The comment in your question gives you the reason why your code is failing. Here is another solution leveraging the use of map:

Python 3, you get map objects that you will have to call list on if you want to see the output as you expect.

>>> res = [list(map(len, x.split())) for x in lucky]
>>> res
[[4, 2, 3, 5, 3, 3, 3], [4, 2, 3, 5, 3, 3, 3], [3, 2, 3, 5, 2, 3, 4], [3, 2, 3, 5, 2, 3, 5]]

Python 2 will give you a list from calling map:

>>> res = [map(len, x.split()) for x in lucky]
>>> res
[[4, 2, 3, 5, 3, 3, 3], [4, 2, 3, 5, 3, 3, 3], [3, 2, 3, 5, 2, 3, 4], [3, 2, 3, 5, 2, 3, 5]]

edited May 23, 2017 at 11:46

CommunityBot

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answered Mar 5, 2017 at 13:22

idjaw

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