Python .join or string concatenation

Question

I realise that if you have an iterable you should always use .join(iterable) instead of for x in y: str += x. But if there\'s only a fixed number of va

Answer 1

I recommend join() over concatenation, based on two aspects:

1. Faster.
2. More elegant.

Regarding the first aspect, here's an example:

import timeit    

s1 = "Flowers"    
s2 = "of"    
s3 = "War"    

def join_concat():    
    return s1 + " " + s2 + " " + s3  

def join_builtin():    
    return " ".join((s1, s2, s3))    

print("Join Concatenation: ", timeit.timeit(join_concat))         
print("Join Builtin:       ", timeit.timeit(join_builtin))

The output:

$ python3 join_test.py
Join Concatenation:  0.40386943198973313
Join Builtin:        0.2666833929979475

Considering a huge dataset (millions of lines) and its processing, 130 milliseconds per line, it's too much.

And for the second aspect, indeed, is more elegant.