SAMS Teach Yourself Perl in 24 Hours THIRD EDITION

Hour 7. Hashes

What You'll Learn in This Hour:

• Create a hash

• Insert and remove elements from a hash

• Use hashes to manipulate arrays

The hash is the third basic data type in Perl. The first data type you learned about was the scalar, which is a simple data type designed to hold one thing (any one thing—of any size—but still one thing). Next came the array, which is a collection of scalars. An array can hold as many scalars as you like, but searching for the scalar value you need in an array usually involves sequential access of the array until you find the scalar you need.

Hashes are another kind of collective data type. Like arrays, hashes contain a number of scalars. The difference between arrays and hashes is that hashes access their scalar data ...