[Chicago] Making a list of strings

Phil Robare verisimilidude at gmail.com
Mon Oct 19 22:34:54 CEST 2009

Thanks to Massimo and Brant for pointing out that my problem is append
returns None.
My problem was that I am sometimes getting a single string and
sometimes getting the result of a list comprehension.  The routine I
am calling takes a list of strings.  I figured that appending either
to a null list would give me the list I wanted.  "Don't work that

Thanks to those who answered.


On Mon, Oct 19, 2009 at 1:13 PM, Massimo Di Pierro
<mdipierro at cs.depaul.edu> wrote:
> because in
> y = list().append(whatever)
> you are bot storing the vaue returned by list() but the value returned by
> append and append does not return the list it acts on. append always returns
> None.
> On Oct 19, 2009, at 1:08 PM, Phil Robare wrote:
>> OK fellow pythonistas,  can anyone explain what is going on here?
>>        I'm using a recent, but not most recent, version of Python.
>> Python 2.5.4 (r254:67916, Dec 23 2008, 15:10:54) [MSC v.1310 32 bit
>> (Intel)]
>>        I want a list with a string value in it.  I make a sample string to
>> put in a list.
>> In [1]: s='string'
>>        The obvious way gives me something different but expected
>> In [2]: list(s)
>> Out[2]: ['s', 't', 'r', 'i', 'n', 'g']
>>        So I try appending something to a newly created empty list
>> In [3]: y=list().append(s)
>>        And I get a null value.  This is unexpected,
>> In [4]: y
>>        since doing the steps independantly gives me what I want.
>> In [5]: y=list()
>> In [6]: y.append(s)
>> In [7]: y
>> Out[7]: ['string']
>> I want to pass this as a parameter and it seems non-pythonic to have
>> to create a variable and then pass it when all I want is a single use.
>> Any ideas for a better work-around?
>> Phil
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