Documentation for method append assembled from the following types:

class Hash

From Hash

(Hash) method append

Defined as:

method append(+@values)

Append the provided Pairs or even sized list to the Hash. If a key already exists, turn the existing value into an Array and push new value onto that Array. Please note that you can't mix even sized lists and lists of Pairs. Also, bare Pairs or colon pairs will be treated as named arguments to .append.

my %h = a => 1;
%h.append('b', 2, 'c', 3);
%h.append( %(d => 4) );
say %h;
# OUTPUT: «{a => 1, b => 2, c => 3, d => 4}␤» 
%h.append('a', 2);
# OUTPUT: «{{a => [1 2], b => 2, c => 3, d => 4}␤»

Note: Compared to push, append will slip in the given value, whereas push will add it as is:

my %hb = :a[42, ]; %hb.append: "a" => <a b c a>;
say %hb; # OUTPUT: «{a => [42 a b c a]}␤» 
 
my %ha = :a[42, ]; %ha.push: "a" => <a b c a>;
say %ha; # OUTPUT: «{a => [42 (a b c a)]}␤»

class Any

From Any

(Any) method append

Defined as:

multi method append(Any:U \SELF: |values --> Array)

In the case the instance is not a positional-thing, it instantiates it as a new Array, otherwise clone the current instance. After that, it appends the values passed as arguments to the array obtained calling Array.append on it.

my $a;
say $a.append; # OUTPUT: «[]␤» 
my $b;
say $b.append((1,2,3)); # OUTPUT: «[1 2 3]␤»

role Buf

From Buf

(Buf) method append

method append( $elems )

Appends at the end of the buffer

$bú.append( @φ[5..10] );
say $bú.perl; # OUTPUT: «Buf.new(1,1,2,3,5,8,13,21,34,55,89)» 

class Array

From Array

(Array) method append

Defined as

sub append(\array, |elems)
multi method append(Array:D: \values)
multi method append(Array:D: **@values is raw)

Appends the argument list to the array passed as the first argument. This modifies the array in-place. Returns the modified array. Throws for lazy arrays.

The difference from method push is that if you append a single array or list argument, append will flatten that array / list, whereas push appends the list / array as just a single element.

Example:

my @a = <a b c>;
my @b = <d e f>;
@a.append: @b;
say @a.elems;               # OUTPUT: «6␤» 
say @a;                     # OUTPUT: «[a b c d e f]␤»

class Nil

From Nil

(Nil) method append

method append(*@)

Warns the user that they tried to append onto a Nil.