The substring(...) function has two variations, not counting syntax variations. It copies a part of a String value into a new String value. The substring(..) function results in null if any of the following conditions is met:
Syntax:
substring( source-string, start-index )
substring( source-string, start-index, end-index )
source-string.substring( start-index )
source-string.substring( start-index, end-index )
| Parameter | Description |
| source-string |
The String from which to copy. |
| start-index |
The position where copying will begin. If start-index is negative, then it is counted backward from the end of source-string. Therefore, -1 is the last character, -2 is the next-to-last and so forth. |
| end-index |
The position where copying will end. If end-index is negative then it is counted backward from the end of source-string. Therefore, -1 is the last character, -2 is the next-to-last and so forth. The character at end-index will not be copied into the new String. In other words, copying includes the character at the start-index but not the character at the end-index. If end-index is omitted, is null or is greater than the length of the source-string, then copying will continue through the end of the source-string. |
| Example Code | Description |
| strVal.substring(0, 5) | Get the first 5 characters of strVal. |
| strVal.substring(-5) | Get the last 5 characters of strVal. |
| strVal.substring(2) | Get all of strVal except the first 2 characters. |
| strVal.substring(0, -2) | Get all of strVal except the last 2 characters. |
| strVal.substring(2, -2) | Get all of strVal except the first 2 characters and the last 2 characters. |