Operator Scope of Action:
Operator First Added:
Where "data" is a string literal, string attribute or expression evaluating to a string.
Where start is the zero-based position to start the substring. Negative start values are not supported, though String.substring() does so and may be used instead.
Where length is the length of the returned string. If not specified, the entire string from (or back from) start is returned.
Extracts a substring of data. For example:
$MyString = substr("test",0,1);
returns "t", while
$MyString = substr("test",1,2);
returns "es". All arguments are evaluated; if the designated characters do not exist, an empty string is returned.
If the length of the substring is negative, it is treated as an offset from the end of the string.
$MyString = substr("Hello",1,-1); → "ell"
Note that in expressions like
the value of $Name is not changed.