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Re^3: do until loops

by Anonymous Monk
on Feb 17, 2014 at 12:24 UTC ( #1075170=note: print w/replies, xml ) Need Help??


in reply to Re: Re: do until loops
in thread do until loops

How to exit ?? alst is not working

Replies are listed 'Best First'.
Re^4: do until loops
by Athanasius (Bishop) on Feb 17, 2014 at 14:25 UTC

    From last:

    last cannot be used to exit a block that returns a value such as eval {}, sub {}, or do {}, and should not be used to exit a grep() or map() operation.

    Note that a block by itself is semantically identical to a loop that executes once. Thus last can be used to effect an early exit out of such a block.

    So, last doesn’t work in a do { ... } until (...); loop. But — put the whole construct inside a block, and last now works fine:

    #! perl use strict; use warnings; my $n = 42; { do { printf "n = %d\n", $n--; last if $n == 37; } until ($n <= 0); } print "Past the loop\n";

    Output:

    0:22 >perl 878_Tutorial.pl n = 42 n = 41 n = 40 n = 39 n = 38 Past the loop 0:22 >

    Hope that helps,

    Athanasius <°(((><contra mundum Iustus alius egestas vitae, eros Piratica,

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