string - An attribute of base type string, an expression that results in a string or a constant string value.
substring - An attribute of base type string, an expression that results in a string or a constant string value.
startIndex - A (positive) integer value indicating at which character the search for the substring should start (inclusive). This can be either an attribute of base type integer, an expression that results in an integer or a constant integer value. The first character starts at index 0.
Return type
integer - the index of the first occurrence of the specified substring or -1 if it is not found
Example
Expression
Result
Type
INDEXOF ( "Hello world" , "o" )
4
Integer
INDEXOF ( "Hello world" , "o" , 5 )
7
Integer
INDEXOF ( "Hello world" , "a" )
-1
Integer
INDEXOF ( "Hello world" , "o" , 8 )
-1
Integer
INDEXOF ( "Hello world" , "o" , -12 )
4
Integer
INDEXOF ( "Hello world" , "o" , 50 )
-1
Integer
There is no restriction on the value of startIndex. If it is negative, it has the same effect as if it were zero: this entire string may be searched. If it is greater than the length of this string, it has the same effect as if it were equal to the length of this string: -1 is returned.