You could evaluate y separately:
yval = <long expression>
for item in x[:-yval] if yval else x:
[do stuff]
or you could do it using the walrus operator:
for item in x[:-yval] if (yval := <long expression>) else x:
[do stuff]
or, perhaps simplest, you could do
for item in x[:-y or None]: # a value of None for a slice argument means
"don't slice here"
[do stuff]
Best wishes
Rob Cliffe
On 26/11/2021 09:17, Frank Millman wrote:
Hi all
In my program I have a for-loop like this -
>>> for item in x[:-y]:
... [do stuff]
'y' may or may not be 0. If it is 0 I want to process the entire list
'x', but of course -0 equals 0, so it returns an empty list.
In theory I can say
>>> for item in x[:-y] if y else x:
... [do stuff]
But in my actual program, both x and y are fairly long expressions, so
the result is pretty ugly.
Are there any other techniques anyone can suggest, or is the only
alternative to use if...then...else to cater for y = 0?
Thanks
Frank Millman
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