[Tutor] Python "returning .split() without empty strings

[Mats Wichmann]

On October 24, 2020 5:14:23 AM MDT, Alan Gauld via Tutor <tutor at python.org> wrote:
>On 24/10/2020 01:44, Chris C wrote:
>> Hi all, I have a question regarding string operations.
>> the following string needs to be chopped up, having the 0's dividing
>the
>> data that I wanted, therefore the string here becomes
>> 
>> # run this
>> string = '1111022220000333300044405550055'
>> string = string.split('0')

there's nothing syntactically wrong with this, but I don't like it: you're reassigning to the name string, and now the name is misleading, because it's a list of strings now. Better to pick a different name, or... skip it as a separate step. See below:

>> 
>> # get this
>> ['1111', '2222', '', '', '', '3333', '', '', '444', '555', '', '55']
>> 
>> # but I want it without the empty strings,
>
>There are (at least) two ways to tackle this.
>One is to do the split using regular expressions to select multiple
>0's.
>
>import re
>string = '1111022220000333300044405550055'
>key_list = re.split('0+',string)  #split on 1 or more 0s
>
>The other is to use a map or generator expression to filter them out.
>Given regex propensity for complicating things I'd usually go with a
>GE:
>
>> key_list = list()
>> for key in string :
>> if key != '':
>> key_list.append(key)
>
>Which is what the above is in disguise...
>
>key_list = [key for key in string if key]

per above, why not combine:

key_list = [key for key in string.split('0') if key]

>It does the same work but is shorter and arguably more readable.


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