Every time you think to yourself, is there a perl function you must to grep perlfunc
perldoc perlfunc |grep -i array
An named array in scalar context is quite different from what would at
Functions for real @ARRAYs
"last", "next", "redo", "return", "sub", "wantarray"
"reset", "scalar", "undef", "wantarray"
$wantarray, $evaltext, $is_require, $hints, $bitmask) = ca
+ller($i);
@array = split(/:/);
returns "undef" when its argument is an empty array, *or* when
Use of "defined" on aggregates (hashes and arrays) is
if (@an_array) { print "has array elements\n" }
Given an expression that specifies a hash element, array
element, hash slice, or array slice, deletes the specified
element(s) from the hash or array. In the case of an array, if
the array elements happen to be at the end, the size of the
array will shrink to the highest element that tests true for
entry from the DBM file. Deleting from a "tie"d hash or array
Deleting an array element effectively returns that position of
the array to its initial, uninitialized state. Subsequently
Note that deleting array elements in the middle of an array wi
+ll
and @ARRAY:
foreach $index (0 .. $#ARRAY) {
delete $ARRAY[$index];
delete @ARRAY[0 .. $#ARRAY];
or undefining %HASH or @ARRAY:
@ARRAY = (); # completely empty @ARRAY
undef @ARRAY; # forget @ARRAY ever existed
final operation is a hash element, array element, hash slice,
+or
array slice lookup:
When the hash is entirely read, a null array is returned in li
+st
"wantarray" for more on how the evaluation context can be
array with more than one value, calls execvp(3) with the
array with one element in it, the argument is checked for shel
+l
Given an expression that specifies a hash element or array
array has ever been initialized, even if the corresponding val
+ue
print "Exists\n" if exists $array[$index];
print "Defined\n" if defined $array[$index];
print "True\n" if $array[$index];
A hash or array element can be true only if it's defined, and
final operation is a hash or array key lookup or subroutine
Although the deepest nested array or hash will not spring into
See "Pseudo-hashes: Using an array as a hash" in perlref for
an "@" character may be taken to mean the beginning of an arra
+y
(This is similar to pre-extending an array by assigning a larg
+er
number to $#array.) If you say
on an entire array or hash to find out how many elements these
have. For that, use "scalar @array" and "scalar keys %hash"
with tied arrays and hashes.
%hash = map { getkey($_) => $_ } @array;
foreach $_ (@array) {
array composed of those items of the original list for which t
+he
%hash = map { "\L$_", 1 } @array # perl guesses EXPR.
+wrong
%hash = map { +"\L$_", 1 } @array # perl guesses BLOCK.
+right
%hash = map { ("\L$_", 1) } @array # this also works
%hash = map { lc($_), 1 } @array # as does this.
%hash = map +( lc($_), 1 ), @array # this is EXPR and wor
+ks!
%hash = map ( lc($_), 1 ), @array # evaluates to (1, @ar
+ray)
@hashes = map +{ lc($_), 1 }, @array # EXPR, so needs , at
+end
pop ARRAY
pop Pops and returns the last value of the array, shortening the
array by one element. Has an effect similar to
$ARRAY[$#ARRAY--]
If there are no elements in the array, returns the undefined
ARRAY is omitted, pops the @ARGV array in the main program, an
+d
the @_ array in subroutines, just like "shift".
Note that if you're storing FILEHANDLES in an array or other
push ARRAY,LIST
Treats ARRAY as a stack, and pushes the values of LIST onto th
+e
end of ARRAY. The length of ARRAY increases by the length of
$ARRAY[++$#ARRAY] = $value;
array.
ARRAY
file in the directories specified in the @INC array.
@INC array and will complain about not finding "Foo::Bar" ther
+e.
(hyphens allowed for ranges). All variables and arrays beginni
+ng
@ARGV and @INC arrays and your %ENV hash. Resets only package
"wantarray"). If no EXPR is given, returns an empty list in li
+st
the returned semid_ds structure or semaphore value array.
packed array of semop structures. Each semop structure can be
shift ARRAY
shift Shifts the first value of the array off and returns it,
shortening the array by 1 and moving everything down. If there
are no elements in the array, returns the undefined value. If
ARRAY is omitted, shifts the @_ array within the lexical scope
of subroutines and formats, and the @ARGV array at file scopes
the same thing to the left end of an array that "pop" and "pus
+h"
splice ARRAY,OFFSET,LENGTH,LIST
splice ARRAY,OFFSET,LENGTH
splice ARRAY,OFFSET
splice ARRAY
array, and replaces them with the elements of LIST, if any. In
list context, returns the elements removed from the array. In
no elements are removed. The array grows or shrinks as
the end of the array. If LENGTH is omitted, removes everything
elements off the end of the array. If both OFFSET and LENGTH a
+re
Example, assuming array lengths are passed before arrays:
into the @_ array. Use of split in scalar context is deprecate
+d,
when you pass it an array as your first argument. The array is
the array as the format, Perl will use the count of elements i
+n
the array as the format, which is almost never useful.
argument in LIST, or if LIST is an array with more than one
"TIESCALAR", "TIEHANDLE", "TIEARRAY", or "TIEHASH"). Typically
A class implementing an ordinary array should have the followi
+ng
TIEARRAY classname, LIST
perltie, Tie::Hash, Tie::Array, Tie::Scalar, and Tie::Handle.
on a scalar value, an array (using "@"), a hash (using "%"), a
return (wantarray ? (undef, $errmsg) : undef) if $they_ble
+w_it;
unshift ARRAY,LIST
the array, and returns the new number of elements in the array
+.
wantarray
return unless defined wantarray; # don't bother doing m
+ore
return wantarray ? @a : "@a";
| 