1.4) Variable Types
Below is a table containing the most common types of variable used within IDL.
| Data Type | Description | Creation |
| Byte | An 8-bit unsigned integer ranging in value from 0 to 255.Pixels in images are commonly represented as byte data. | a = 5Ba = BYTE(5) |
| Integer | A 16-bit signed integer ranging in value from -32,768 to +32,767. | b = 0b = FIX(0) |
| Long | A 32-bit signed integer ranging in value from-2,147,483,648 to +2,147,483,647. | d = 0Ld = LONG(0) |
| 64-Bit Long | A 64-bit signed integer ranging in value from-9,223,372,036,854,775,808 to +9,223,372,036,854,775,807. | f = 0LLf = LONG64(0) |
| Floating Point | A 32-bit single precision, floating point number in the range of ±1038,with approximately 6 or 7 significant digits. | h = 0.0h = FLOAT(0) |
| Double Precision | A 64-bit double precision, floating point number in the range of ±10308,with approximately 14 significant digits. | i = 0.0Di = DOUBLE(0) |
| Complex | A real-imaginary pair of single precision, floating point numbers.Complex numbers are useful for signal processing and frequency domain filtering. | j = COMPLEX(1,0) |
| Double Precision Complex | A real-imaginary pair of double precision, floating point numbers. | k = DCOMPLEX(1.0,0.0) |
| String | A sequence of characters, from 0 to 2,147,483,647 (2.1Gb)characters in length, which is interpreted as text. | X = 'Hello' |