Concatenate elements of a tuple in a list in python

Question

I have a list of tuples that has strings in it For instance:

[(\'this\', \'is\', \'a\', \'foo\', \'bar\', \'sentences\')
(\'is\', \'a\', \'foo\', \'bar\', \'         


        

Answer 1

The list comprehension creates temporary strings. Just use ' '.join instead.

>>> words_list = [('this', 'is', 'a', 'foo', 'bar', 'sentences'),
...               ('is', 'a', 'foo', 'bar', 'sentences', 'and'),
...               ('a', 'foo', 'bar', 'sentences', 'and', 'i'),
...               ('foo', 'bar', 'sentences', 'and', 'i', 'want'),
...               ('bar', 'sentences', 'and', 'i', 'want', 'to'),
...               ('sentences', 'and', 'i', 'want', 'to', 'ngramize'),
...               ('and', 'i', 'want', 'to', 'ngramize', 'it')]
>>> new_list = []
>>> for words in words_list:
...     new_list.append(' '.join(words)) # <---------------
... 
>>> new_list
['this is a foo bar sentences', 
 'is a foo bar sentences and', 
 'a foo bar sentences and i', 
 'foo bar sentences and i want', 
 'bar sentences and i want to', 
 'sentences and i want to ngramize', 
 'and i want to ngramize it']

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Above for loop can be expressed as following list comprehension:

new_list = [' '.join(words) for words in words_list]