Re^3: filtering an array

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Re^4: filtering an array by prbndr (Acolyte) on Sep 01, 2012 at 22:48 UTC
i see. so if my array @positions is already defined and created, do i need to loop over all the values in @positions and then execute the code you posted? something like: `for (@positions) {@positions = grep $_->[1] =~ /ac/i, @positions;}` and then: `for (@positions) {@positions = map $_->[0], @positions;}`	[reply] [d/l] [select]
Re^5: filtering an array by philiprbrenan (Monk) on Sep 01, 2012 at 23:03 UTC
Likewise, the for is unnecessary in this code too: `for (@positions) {@positions = map $_->[0], @positions;}` [download] It should just be: `@positions = map $_->[0], @positions;` [download] because map iterates over the array you give it. Even better, you could write: `$_ = $_->[0] for @positions;` [download] here we are making the for implicit in map explicit.	[reply] [d/l] [select]
Re^6: filtering an array by prbndr (Acolyte) on Sep 01, 2012 at 23:15 UTC
perl still has a problem with this: `@positions = grep $_->[1] =~ /ac/i, @positions;` with the same error Use of uninitialized value in pattern match (m//)	[reply] [d/l]
Re^7: filtering an array by philiprbrenan (Monk) on Sep 01, 2012 at 23:19 UTC
Re^8: filtering an array by prbndr (Acolyte) on Sep 01, 2012 at 23:39 UTC
Re^5: filtering an array by philiprbrenan (Monk) on Sep 01, 2012 at 22:59 UTC
You do not need the for becuase grep loops over the array you give it. Please change: `for (@positions) {@positions = grep $_->[1] =~ /ac/i, @positions;}` [download] to: `@positions = grep $_->[1] =~ /ac/i, @positions;` [download]	[reply] [d/l] [select]
Re^6: filtering an array by prbndr (Acolyte) on Sep 01, 2012 at 23:03 UTC
right, but the error still persists. what here isn't defined?	[reply]