Combining lists to dictionary

Roy Smith roy at panix.com
Wed Nov 12 02:06:47 CET 2014


In article <m3tscl$f1e$2 at dont-email.me>,
 Denis McMahon <denismfmcmahon at gmail.com> wrote:

> Hi
> 
> Given x,y are a lists of keys and value that I wish to combine to a 
> dictionary, such that x[n] is the key for value y[n], which is preferred:
> 
> z = {a:b for (a,b) in zip(x,y)}
> z = {x[n]:y[n] for n in range(min(len(x),len(y)))}
> 
> The zip feels more elegant, but it seems clunky to use the zip method to 
> create a list of tuples just to split them up into key:value pairs.

I would definitely use the first one.  It's so much easier to read.  If 
I was worried that the lists might be so long that the cost of building 
the intermediate list mattered, I'd use izip() instead of zip().



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