Substring

Description

The substring function takes a string and returns a certain part of the string, based on a start and a length.

Syntax

substring(string subject, number start, number length)

• subject is the string to take a substring from.
• start is the index of the first character to include in the substring (0-based).
• length is the number of characters to include in the substring. Must be greater than or equal to 0.

Remarks

• If start is greater than the number of characters in the string - 1, the function will return an empty string.
• If length is 0 or negative, the function will return an empty string.
• If start + length is greater than the number of characters remaining in the string, the substring will be truncated to the remaining characters.
• If start or length is not an integer, it will be rounded to the nearest integer (0.5 rounds up).
• If start is negative, it is treated as starting from the end of the subject. For example, if start is -3 and length is 3, the function will return the last 3 characters of the string. If the absolute value is greater than the number of characters in subject, an empty string is returned.

Examples

substring("Hello, world!", 0, 5)   // "Hello"
substring("Hello, world!", 7, 5)   // "world"
substring("Hello, world!", 7, 100) // "world!"
substring("Hello, world!", 7, 0)   // ""
substring("Hello, world!", 7, -1)  // ""
substring("Hello, world!", 7, 1.5) // "wo"
substring("Hello, world!", 7.5, 1) // "o"
substring("Hello, world!", 14, 5)  // ""
substring("Hello, world!", -14, 5) // ""
substring("Hello, world!", -1, 3)  // "!"
substring("Hello, world!", -2, 3)  // "d!"
substring("Hello, world!", -3, 3)  // "ld!"
substring("Hello, world!", -4, 3)  // "rld"
substring("Hello, world!", -13, 5) // "Hello"