CODEWITHSUNDEEP
pythonstringlist
jdoe
jdoe

Reputation: 654

Convert lists of lists of string into a list of string efficently

I have a lists of lists of strings which I would like to convert to a list of strings adding a space between each list item. eg.

original_list = [['the', 'cat', 'in', 'the', 'hat'], ['fat', 'cat', 'sat', 'on', 'the', 'mat']]

desired_output = ['the cat in the hat', 'fat cat sat on the mat']

I understand that I can do it using this:

desired_output
for each in original_list:
    desired_output.append(' '.join(each))

but as I am working with large amounts of data am ideally looking for a more efficient way to do this.

Upvotes: 0

Views: 75

Answers (2)

Rafael Aguilar
Rafael Aguilar

Reputation: 3279

Another pythonic and simple way, in Python 3, could be using map, says another SO discussion it should be faster, it would go like this:

original_list = [['the', 'cat', 'in', 'the', 'hat'], ['fat', 'cat', 'sat', 'on', 'the', 'mat']]

#              (------where magic happens--------)
desired_list = list(map(' '.join, original_list ))

#print
#output ['the cat in the hat', 'fat cat sat on the mat']

Upvotes: 1

Ajax1234
Ajax1234

Reputation: 71451

Use str.join with a full space ' ':

original_list = [['the', 'cat', 'in', 'the', 'hat'], ['fat', 'cat', 'sat', 'on', 'the', 'mat']]
final_list = [' '.join(i) for i in original_list]

Output:

['the cat in the hat', 'fat cat sat on the mat']

Upvotes: 4

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