Re^2: How to build a hash?

[Jasper]

No, like an array element ($array[$n]) the accessor of a hash element ($hash{'foo'}) is also an lvalue (basically you can assign a value to it). This method of accessing or modifying one value at a time doesn't affect the rest of the hash.

You can also modify several elements at once using a hash slice, for example

@hash{'foo','bar','baz'} = (1,2,3);

Only when you say %hash are you definitely effecting the entire hash.

%hash = ('foo',1,'bar',2'baz',3); # whole hash overwritten
$hash{foo} = 1; # only one element created or modified
@hash{@array} = (1,2,3); # only elements specified in @array overwritt
+en, or created.