first

Return the first list element for which a block returns true.

תקציר

my $val = first { BLOCK } @list;
my $d   = first { defined } @list;
my $big = first { $_ > 100 } @values;

For each element first sets $_ to that element and calls the block in scalar context; the first element for which the block returns true is returned. Remaining elements are not examined.

מה מוחזר

The matching element (the original value, not the block’s return). If no element matches - or the list is empty - returns undef.

דוגמאות

my $first_defined = first { defined $_ } @list;
my $first_big     = first { $_ > $threshold } @measurements;
my $first_admin   = first { $_->is_admin } @users;

הבדלים מן ה-upstream

Fully compatible with upstream.

ראו גם

• any - boolean ”at least one matches“ test.

• grep - collect every matching element.

• pairfirst - pair-oriented counterpart.