How to concatenate a string to each element of a list of strings?

Question

I have the following list:

sentence = ['doc1','doc2','doc3','doc4']

How can I concatenate .txt at the end of each elment of sentece? (*):

['doc1.txt','doc2.txt','doc3.txt','doc4.txt']

I tried to list comprehension:

'.txt '.join(sentence[:-1])

Nonetheless, it returns this:

'doc1.txt doc2.txt doc3'

Which is wrong, since it's different from (*)

AChampion · Accepted Answer · 2017-04-08 01:05:16Z

2

You aren't trying to join the whole string together just add .txt to each string:

>>> [s + '.txt' for s in sentence]
['doc1.txt', 'doc2.txt', 'doc3.txt', 'doc4.txt']

Not sure why you are slicing off the last element.

answered Apr 8, 2017 at 1:05

AChampion

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1 Comment

I see... thanks for helping me to clarify this issue.

return007 · Accepted Answer · 2017-04-08 04:39:50Z

2

Another approach :

>>> sentence = ['doc1','doc2','doc3','doc4']
>>> list(map(lambda x : x + '.txt', sentence))
['doc1.txt', 'doc2.txt', 'doc3.txt', 'doc4.txt']

answered Apr 8, 2017 at 4:39

return007

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Deba · Accepted Answer · 2017-04-08 04:40:10Z

1

You may use map and lambda

map(lambda x:x+'.txt', sentence)

output:

['doc1.txt', 'doc2.txt', 'doc3.txt', 'doc4.txt']

answered Apr 8, 2017 at 4:40

Deba

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