Perl's @foo[3,7,1,-1] ?

kj at
Sat Jun 13 14:11:11 EDT 2009

Switching from Perl here, and having a hard time letting go...

Suppose I have an "array" foo, and that I'm interested in the 4th, 8th,
second, and last element in that array.  In Perl I could write:

  my @wanted = @foo[3, 7, 1, -1];

I was a bit surprised when I got this in Python:

>>> wanted = foo[3, 7, 1, -1]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: list indices must be integers

Granted, Perl's syntax is often obscure and hard-to-read, but in
this particular case I find it quite transparent and unproblematic,
and the fictional "pythonized" form above even more so.

The best I've been able to come up with in Python are the somewhat

>>> wanted = map(foo.__getitem__, (3, 7, 1, -1))

or the clearer but unaccountably sesquipedalian

>>> wanted = [foo[i] for i in 3, 7, 1, -1]
>>> wanted = [foo[3], foo[7], foo[7], foo[-1]]

Are these the most idiomatically pythonic forms?  Or am I missing
something better?



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