Built-in Functions for Strings

The functions sprintf and sscanf will be presented in their own sections, below.

Check if it is a string
```
  stringp(something)
```
The function stringp returns 1 if the value something is a string, otherwise 0.
Finding the size
```
  sizeof(string)
```
or
```
  strlen(string)
```
Returns the length (that is, the number of characters) in the string string.
```
  sizeof("hi ho")
```
gives the result:
```
  5
```
```
  sizeof("")
```
gives the result:
```
  0
```
The function strlen is a synonym for
```
  sizeof
```
Reversing a string
```
  reverse(string)
```
returns a new string with the characters in reverse order.
```
  reverse("foo")
```
gives the result:
```
  "oof"
```
Replacing parts in a string
```
  replace(string, old, new)
```
returns a new string where all occurrences of the string old have been replaced with the string new:
```
  replace("fooFOOfoo", "foo", "fum")
```
gives the result:
```
  "fumFOOfum"
```
Converting to lower case
```
  lower_case(string)
```
returns a new string where all upper-case characters in the string string have been turned to lower case:
```
  lower_case("A Foo IS!")
```
gives the result:
```
  "a foo is!"
```
Converting to upper case
```
  upper_case(string)
```
returns a new string where all lower-case characters in the string string have been turned to upper case:
```
  upper_case("A Foo IS!")
```
gives the result:
```
  "A FOO IS!"
```
Capitalizing
```
  String.capitalize(string)
```
If the first character in the string string is a lower-case character, it is converted to upper case:
```
  String.capitalize("xyz-Foo")
```
gives the result:
```
  "Xyz-Foo"
```
Finding a substring in a string
```
  search(haystack, needle)
```
returns the index of the start of the first occurrence of the string needle in the string haystack:
```
  search("sortohum", "orto")
```
gives the result:
```
  1
```