Description

Replaces a substring in variable with a specified string.

Syntax

variable [start, length] = expression

Parameters

The brackets operator has the following parameters when used for insertion. Use start and length to define the substring.

ParameterDescription
StartA positive or negative integer.
  • If start is a positive number, the operation will begin at the character in the start position, counting right from the first character or space at the beginning of the string.
  • If start is a negative number, the operation will begin at the character in that position, counting left from the last character or space at the end of the string.
  • If start is 0 (zero) or 1, the operation will begin with the first character or space at the beginning of the string.
LengthNumber of characters to replace, beginning from start.

Each space and character within the string is counted as a character position. Also, note that the value specified for length includes the character position specified by start.

Note: Length can be negative, signifying reverse order.

expressionReplaces the substring in variable that has been defined by the parameters start and length. If expression yields a string that is longer than the specified substring, the total string length of variable will increase. If expression yields a shorter string, then the total string length of variable decreases.

In other words, the entire substring defined by start and length is replaced by whatever is the value of expression.

Example

The following example The following example shows how to use the brackets operator for insertion.

* When LENGTH = 0. This yields "ABXXYYCDEF"
string = "ABCDEF"
string[-4,0] = "XXYY"

/* When LENGTH = negative number, the reverse order: yields "A123EF"  */
string = "ABCDEF"
string[4,-3] = "123"
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