array – arrays of numeric data

This module defines the array.array type: a space-efficient sequence of values of a single fixed numeric type, indexable like a list but backed by a contiguous block of memory accessible via the buffer protocol.

Supported type codes

The single-character typecode argument selects the element type:

Type code

C type

Bytes

Python type

'b'

signed char

1

int

'B'

unsigned char

1

int

'h'

signed short

2

int

'H'

unsigned short

2

int

'i'

signed int

2 or 4

int

'I'

unsigned int

2 or 4

int

'l'

signed long

4

int

'L'

unsigned long

4

int

'q'

signed long long

8

int

'Q'

unsigned long long

8

int

'f'

float

4

float

'd'

double

8

float

The 'f' and 'd' codes require firmware built with floating-point support (the default on most boards). The exact width of 'i' and 'I' follows the host C ABI — typically 4 bytes on the Cortex-M ports.

Classes

class array.array(typecode: str, iterable: Iterable = ())

Create array with elements of given type. Initial contents of the array are given by iterable. If it is not provided, an empty array is created.

In addition to the methods below, array objects also implement the buffer protocol. This means the contents of the entire array can be accessed as raw bytes via a memoryview or other interfaces which use this protocol.

append(val: Any) → None

Append new element val to the end of array, growing it.

extend(iterable: Iterable) → None

Append new elements as contained in iterable to the end of array, growing it.

__getitem__(index: int | slice) → Any

Indexed read of the array, called as a[index] (where a is an array). Returns a value if index is an int and an array if index is a slice. Negative indices count from the end and IndexError is thrown if the index is out of range.

Note: __getitem__ cannot be called directly (a.__getitem__(index) fails) and is not present in __dict__, however a[index] does work.

__setitem__(index: int | slice, value: Any) → None

Indexed write into the array, called as a[index] = value (where a is an array). value is a single value if index is an int and an array if index is a slice. Negative indices count from the end and IndexError is thrown if the index is out of range.

Note: __setitem__ cannot be called directly (a.__setitem__(index, value) fails) and is not present in __dict__, however a[index] = value does work.

__len__() → int

Returns the number of items in the array, called as len(a) (where a is an array).

Note: __len__ cannot be called directly (a.__len__() fails) and the method is not present in __dict__, however len(a) does work.

__add__(other: array) → array

Return a new array that is the concatenation of the array with other, called as a + other (where a and other are both arrays).

Note: __add__ cannot be called directly (a.__add__(other) fails) and is not present in __dict__, however a + other does work.

__iadd__(other: array) → array

Concatenates the array with other in-place, called as a += other (where a and other are both arrays). Equivalent to extend(other).

Note: __iadd__ cannot be called directly (a.__iadd__(other) fails) and is not present in __dict__, however a += other does work.

__repr__() → str

Returns the string representation of the array, called as str(a) or repr(a) (where a is an array). Returns the string "array(<type>, [<elements>])", where <type> is the type code letter for the array and <elements> is a comma separated list of the elements of the array.

Note: __repr__ cannot be called directly (a.__repr__() fails) and is not present in __dict__, however str(a) and repr(a) both work.