Core Function SubStr

SubStr( <expression>, <start>, <count>, <replacement> )

Description

Return part of a string

Parameters

expression

The expression to evaluate.

start

The character position to start. (0 = first character)

OR

If the start is a negative value the character position will work backwards from the length of the string.

count

Optional; The number of characters to extract. By default the entire remainder of the string.

If count is given and is negative, then that many characters will be omitted from the end of string (after the start position has been calculated when a start is negative). If start denotes the position of this truncation or beyond, empty string will be returned.

(Note - If you wish to extract from a start to a end position instead of from start to a number of characters you should see Sub())

replacement

Optional; If you set this parameter the substring will be replaced instead of returned so you will receive a new string with the substring replaced with the replacement text.

Return Value

Success: Returns the extracted string.

Failure: Returns an empty string.

Remarks

None.

Example

$var = Substr("I am a string", 2, 2);
MsgBox("2 chars extracted from position 2 are: $var");

Example using Start as a negative number

say substr("UberFoX", -3); // Prints FoX
say substr("UberFoX", -4, 2); // Prints rF

Using replacement and returning a new string

$str = "UberCat!";
print substr($str, 4, 3, "FoX");
# Prints
# UberFoX!

Example of using an array as the second param

my $str = "the quick brown fox";
my $needle = "quick";
my $start = strpos($str, $needle);
my $len = strlen($needle);
my $arr = array($start, $len);
say substr($str, $arr); // Prints "quick"
 
# Slghtly better than doing substr($str, $arr[0], $arr[1]);