list comprehensions value assignment syntax error

[Gerrit Holl]

Hans Nowak schreef op woensdag  8 januari om 01:47:01 +0000:
> Gerrit Holl wrote:
> 
> >I am trying to assign to a list item using list comprehensions, but this
> >raises a SyntaxError:
> >
> >>>>[l[i] = chr(i) for i in range(256)]
> >>>
> >   File "<stdin>", line 1
> >       [l[i] = chr(i) for i in range(256)]
> >	             ^
> >				 SyntaxError: invalid syntax
> >
> >Why?
> 
> The first part of a list comprehension must be an expression. An assignment 
> like l[i] = chr(i) is a statement.

Ah, I see. Thank you for your help, I did not realise this.

> As others have pointed out, you can write this as
> 
>   l = [chr(i) for i in range(256)]
> 
> or, if you don't want to rebind l to a new object,
> 
>   l[:] = [chr(i) for i in range(256)]

I now realise my problem did only rise because my list is 2-dimensional,
e.g. I can do:

>>> L[3][2:7] = range(5) # or with list comprehension instead of range(5)
...but I can't do:
>>> L[2:7][3] = range 5
...or of course this does something very different.

yours,
Gerrit.

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