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I've never known the difference, if there is one, between the following:
my %hash;
my %hash = ();
Could anyone shed some light on this?
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Perl uses the ‘%’ symbol as the variable sigil for hashes. This command will declare an empty hash: Similar to the syntax for arrays, hashes can also be declared using a list of comma separated values:
Empty Hash: A hash variable without any key is called empty hash. Here rateof is the hash variable. Inserting a key/value pair into a Hash: Keys are always of string type and values always of scalar type. Here the key is mango and value is 45.
Hash#empty? () is a Hash class method which checks whether the Hash array has any key-value pair. Syntax: Hash.empty? () Hash a empty? form : false Hash b empty? form : false Hash c empty? form : false # emoty? Value Hash a empty? form : false Hash b empty? form : true Hash c empty? form : false
Size of a hash: The number of key/value pairs is known as the size of hash. To get the size, the first user has to create an array of keys or values and then he can get the size of the array. Adding and Removing Elements in Hashes: User can easily add a new pair of key/values into a hash using simple assignment operator.
In some languages, new variables are provided uninitialized. In Perl, scalars are created undefined, and array and hashes are created empty.
The second is wasteful. Assigning an empty list to an empty hash has no effect.
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