Perl - Data Types
Perl is a loosely typed language and there is no need to specify a type
for your data while using in your program. The Perl interpreter will
choose the type based on the context of the data itself.
Perl has three basic data types − scalars, arrays of scalars, and hashes
of scalars, also known as associative arrays. Here is a little detail
about these data types.
| S.N. | Types and Description |
|---|---|
| 1 | Scalar −
Scalars are simple variables. They are preceded by a dollar sign ($). A
scalar is either a number, a string, or a reference. A reference is
actually an address of a variable, which we will see in the upcoming
chapters.
|
| 2 | Arrays −
Arrays are ordered lists of scalars that you access with a numeric index
which starts with 0. They are preceded by an "at" sign (@).
|
| 3 | Hashes −
Hashes are unordered sets of key/value pairs that you access using the
keys as subscripts. They are preceded by a percent sign (%).
|
Numeric Literals
Perl stores all the numbers internally as either signed integers or
double-precision floating-point values. Numeric literals are specified
in any of the following floating-point or integer formats −
| Type | Value |
|---|---|
| Integer | 1234 |
| Negative integer | -100 |
| Floating point | 200.0 |
| Scientific notation | 16.12E14 |
| Hexadecimal | 0xffff |
| Octal | 0577 |
String Literals
Strings are sequences of characters. They are usually alphanumeric
values delimited by either single (') or double (") quotes. They work
much like UNIX shell quotes where you can use single quoted strings and
double quoted strings.
Double-quoted string literals allow variable interpolation, and
single-quoted strings are not. There are certain characters when they
are proceeded by a back slash, have special meaning and they are used to
represent like newline (\n) or tab (\t).
You can embed newlines or any of the following Escape sequences directly in your double quoted strings −
| Escape sequence | Meaning |
|---|---|
| \\ | Backslash |
| \' | Single quote |
| \" | Double quote |
| \a | Alert or bell |
| \b | Backspace |
| \f | Form feed |
| \n | Newline |
| \r | Carriage return |
| \t | Horizontal tab |
| \v | Vertical tab |
| \0nn | Creates Octal formatted numbers |
| \xnn | Creates Hexideciamal formatted numbers |
| \cX | Controls characters, x may be any character |
| \u | Forces next character to uppercase |
| \l | Forces next character to lowercase |
| \U | Forces all following characters to uppercase |
| \L | Forces all following characters to lowercase |
| \Q | Backslash all following non-alphanumeric characters |
| \E | End \U, \L, or \Q |