Create a Hash: Difference between revisions
Content added Content deleted
m (fix redirect) |
|||
| (19 intermediate revisions by 12 users not shown) | |||
| Line 1: | Line 1: | ||
#REDIRECT [[Associative array/Creation]] |
|||
{{task}} |
|||
Create a Hash object that links keys to values and returns a pre-specified element when a key is unknown. |
|||
==[[Perl]]== |
|||
'''Interpeter:''' Perl |
|||
Defining a Hash |
|||
# using => key does not need to be quoted unless it contains special chars |
|||
my %hash = ( |
|||
key1 => 'val1', |
|||
'key-2' => 2, |
|||
three => -238.83, |
|||
4 => 'val3', |
|||
); |
|||
# using , both key and value need to be quoted if containing something non-numeric in nature |
|||
my %hash = ( |
|||
'key1' => 'val1', |
|||
'key-2' => 2, |
|||
'three' => -238.83, |
|||
4 => 'val3', |
|||
); |
|||
Defining a HashRef |
|||
my $hashref = { |
|||
key1 => 'val1', |
|||
'key-2' => 2, |
|||
three => -238.83, |
|||
4 => 'val3', |
|||
} |
|||
Using a Hash |
|||
print $hash{'key1'}; |
|||
$hash{'key1'} = 'val1'; |
|||
@hash{'key1', 'three'} = ('val1', -238.83); |
|||
Using a HashRef |
|||
print $hash->{'key1'}; |
|||
$hash->{'key1'} = 'val1'; |
|||
@hash->{'key1', 'three'} = ('val1', -238.83); |
|||
==[[Ruby]]== |
|||
#a hash object that returns nil for unknown keys |
|||
hash={} |
|||
hash[666]='devil' |
|||
hash[777] # => nil |
|||
hash[666] # => 'devil' |
|||
#a hash object that returns 'unknown key' for unknown keys |
|||
hash=Hash.new('unknown key') |
|||
hash[666]='devil' |
|||
hash[777] # => 'unknown key' |
|||
hash[666] # => 'devil' |
|||
#a hash object that returns "unknown key #{key}" for unknown keys |
|||
hash=Hash.new{|h,k|h[k]="unknown key #{k}"} |
|||
hash[666]='devil' |
|||
hash[777] # => 'unknown key 777' |
|||
hash[666] # => 'devil' |
|||
Latest revision as of 19:09, 9 March 2013
Redirect to: