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Diffstat (limited to 'pod')
| -rw-r--r-- | pod/perlfunc.pod | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/pod/perlfunc.pod b/pod/perlfunc.pod index 3686736fcf..612b9cdd70 100644 --- a/pod/perlfunc.pod +++ b/pod/perlfunc.pod @@ -4758,6 +4758,15 @@ inconsistent results (sometimes saying C<$x[1]> is less than C<$x[2]> and sometimes saying the opposite, for example) the results are not well-defined. +Because C<< <=> >> returns C<undef> when either operand is C<NaN> +(not-a-number), and because C<sort> will trigger a fatal error unless the +result of a comparison is defined, when sorting with a comparison function +like C<< $a <=> $b >>, be careful about lists that might contain a C<NaN>. +The following example takes advantage of the fact that C<NaN != NaN> to +eliminate any C<NaN>s from the input. + + @result = sort { $a <=> $b } grep { $_ == $_ } @input; + =item splice ARRAY,OFFSET,LENGTH,LIST =item splice ARRAY,OFFSET,LENGTH |