jython and concatenation of strings

Steven Bethard steven.bethard at gmail.com
Mon Dec 13 18:24:52 CET 2004


Jan Gregor wrote:
> Hello
>  
>  I found that price of += operator on string is too high in jython. For
>  example 5000 such operations took 90 seconds (i generated html copy of
>  table with 1000 rows and 5 columns). Generation of row data into separate
>  string and joining after lead to time 13 seconds !!!
> 
>  What's alternative way to do that ? (similiar parts of my code are terribbly
>  slow and such simple solution as above didn't help).

I don't use Jython, but are you not able to do something like:

string_list = []
for ... in ...:
     ...
     string_list.append(...)
     ...
string = ''.join(string_list)

This is the usual Python idiom and is usually faster than the += idiom.

Note too that +ing strings in Java also has this problem -- hence 
StringBuffer or whatever it's called.

Steve



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