Concatenate python string from list entries

Question

Lets say that I have a list of strings that I would like to jam together into a single string separated by underscores. I know I can do this using a loop, but python does a lot of things without loops. Is there something in python that already has this functionality? For example I have:

string_list = ['Hello', 'there', 'how', 'are', 'you?']

and I want to make a single string like:

'Hello_there_how_are_you?'

What I have tried:

mystr = ''    
mystr.join(string_list+'_')

But this gives a "TypeError: can only concatenate list (not "str") to list". I know its something simple like this, but its not immediately obvious.

score 35 · Accepted Answer · answered Apr 10 '15 at 16:39

35

You use the joining character to join the list:

string_list = ['Hello', 'there', 'how', 'are', 'you?']
'_'.join(string_list)

Demo:

>>> string_list = ['Hello', 'there', 'how', 'are', 'you?']
>>> '_'.join(string_list)
'Hello_there_how_are_you?'

answered Apr 10 '15 at 16:39

Martijn Pieters

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score 1 · Answer 2 · answered Apr 10 '15 at 16:41

1

Got it I used:

mystr+'_'.join(string_list)
'Hello_there_how_are_you?'

I wanted to use the join function from the string, not the list. Seems obvious now.

answered Apr 10 '15 at 16:41

veda905

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2

You don't need to use `mystr` at all here; it is just an empty string. – Martijn Pieters Apr 10 '15 at 16:45

Concatenate python string from list entries

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