rhai/doc/src/language/string-fn.md

Built-in String Functions
========================

{{#include ../links.md}}

The following standard methods (mostly defined in the [`MoreStringPackage`][packages] but excluded if
using a [raw `Engine`]) operate on [strings]:

| Function                  | Parameter(s)                                                                    | Description                                                                                                             |
| ------------------------- | ------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------- |
| `len` method and property | _none_                                                                          | returns the number of characters (not number of bytes) in the string                                                    |
| `pad`                     | 1) target length<br/>2) character/string to pad                                 | pads the string with a character or a string to at least a specified length                                             |
| `+=` operator, `append`   | character/string to append                                                      | Adds a character or a string to the end of another string                                                               |
| `clear`                   | _none_                                                                          | empties the string                                                                                                      |
| `truncate`                | target length                                                                   | cuts off the string at exactly a specified number of characters                                                         |
| `contains`                | character/sub-string to search for                                              | checks if a certain character or sub-string occurs in the string                                                        |
| `index_of`                | 1) character/sub-string to search for<br/>2) _(optional)_ start index           | returns the index that a certain character or sub-string occurs in the string, or -1 if not found                       |
| `sub_string`              | 1) start index<br/>2) _(optional)_ number of characters to extract, none if < 0 | extracts a sub-string (to the end of the string if length is not specified)                                             |
| `split`                   | delimiter character/string                                                      | splits the string by the specified delimiter, returning an [array] of string segments; not available under [`no_index`] |
| `crop`                    | 1) start index<br/>2) _(optional)_ number of characters to retain, none if < 0  | retains only a portion of the string                                                                                    |
| `replace`                 | 1) target character/sub-string<br/>2) replacement character/string              | replaces a sub-string with another                                                                                      |
| `trim`                    | _none_                                                                          | trims the string of whitespace at the beginning and end                                                                 |

Examples
--------

```rust
let full_name == " Bob C. Davis ";
full_name.len == 14;

full_name.trim();
full_name.len == 12;
full_name == "Bob C. Davis";

full_name.pad(15, '$');
full_name.len == 15;
full_name == "Bob C. Davis$$$";

let n = full_name.index_of('$');
n == 12;

full_name.index_of("$$", n + 1) == 13;

full_name.sub_string(n, 3) == "$$$";

full_name.truncate(6);
full_name.len == 6;
full_name == "Bob C.";

full_name.replace("Bob", "John");
full_name.len == 7;
full_name == "John C.";

full_name.contains('C') == true;
full_name.contains("John") == true;

full_name.crop(5);
full_name == "C.";

full_name.crop(0, 1);
full_name == "C";

full_name.clear();
full_name.len == 0;
```