Perl "hash key exists" FAQ: How can I test to see if a key exists in a Perl hash?
Many times when working with a Perl hash, you need to know if a certain key already exists in the hash. The Perl exists function lets you easily determine if a key already exists in the hash.
A Perl hash key exists example
Here's a simple example that demonstrates the Perl "exists" hash function. In this Perl script we'll first create a simple Perl hash, and then we'll use the exists function to see if the hash key named 'coke' exists in the hash.
First, we create a simple Perl hash:
# create a perl hash
$prices{'pizza'} = 12.00;
$prices{'coke'} = 1.25;
$prices{'sandwich'} = 3.00;
Next, we use the Perl exists function to see if the key exists in our Perl hash:
# if the key exists in the hash,
# execute the print statement
if (exists($prices{'coke'}))
{
print "found the key 'coke' in the hash\n";
}
As you can see from the code, the hash key coke does indeed exist, so the Perl print statement shown will be executed.
Of course this example is very simple, but I hope it helps to demonstrate the Perl exists function in combination with a key in a Perl hash.
Related "hash in Perl" tutorials
I hope you found this short Perl hash tutorial helpful. We have many more Perl hash tutorials on this site, including the following:
Getting started Perl hash tutorials:
- Perl hash introduction/tutorial
- Perl foreach and while: how to loop over the elements in a Perl hash
- Perl hash add - How to add an element to a Perl hash
- How to print each element in a Perl hash
More advanced Perl hash tutorials:
The hash in Perl - hash sorting tutorials:
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