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Arrays in awk

An array is a table of values called elements. The elements of an array are distinguished by their indices. Indices may be either numbers or strings.

This chapter describes how arrays work in awk, how to use array elements, how to scan through every element in an array, and how to remove array elements. It also describes how awk simulates multidimensional arrays, as well as some of the less obvious points about array usage. The chapter finishes with a discussion of gawk's facility for sorting an array based on its indices.

awk maintains a single set of names that may be used for naming variables, arrays, and functions (see User-Defined Functions). Thus, you cannot have a variable and an array with the same name in the same awk program.

• Array Intro: Introduction to Arrays
• Reference to Elements: How to examine one element of an array.
• Assigning Elements: How to change an element of an array.
• Array Example: Basic Example of an Array
• Scanning an Array: A variation of the for statement. It loops through the indices of an array's existing elements.
• Delete: The delete statement removes an element from an array.
• Numeric Array Subscripts: How to use numbers as subscripts in awk.
• Uninitialized Subscripts: Using Uninitialized variables as subscripts.
• Multi-dimensional: Emulating multidimensional arrays in awk.
• Multi-scanning: Scanning multidimensional arrays.
• Array Sorting: Sorting array values and indices.