# `array` — Efficient arrays of numeric values

This module defines an object type which can compactly represent an array of basic values: characters, integers, floating-point numbers, complex numbers. Arrays are mutable sequence types and behave very much like lists, except that the type of objects stored in them is constrained. The type is specified at object creation time by using a type code. The following type codes are defined:

Código de tipo | Tipo C | Tipo Python | Tamaño mínimo en bytes | Notas
--- | --- | --- | --- | ---
`'b'` | signed char | int | 1 |
`'B'` | unsigned char | int | 1 |
`'w'` | Py_UCS4 | Carácter unicode | 4 | (1)
`'h'` | signed short | int | 2 |
`'H'` | unsigned short | int | 2 |
`'i'` | signed int | int | 2 |
`'I'` | unsigned int | int | 2 |
`'l'` | signed long | int | 4 |
`'L'` | unsigned long | int | 4 |
`'q'` | signed long long | int | 8 |
`'Q'` | unsigned long long | int | 8 |
`'e'` | _Float16 | float | 2 | (2)
`'f'` | float | float | 4 |
`'d'` | double | float | 8 |
`'Zf'` | float complex | complex | 8 | (3)
`'Zd'` | double complex | complex | 16 | (3)

Notas:

1. Added in version 3.13.

2. The IEEE 754 binary16 «half precision» type was introduced in the 2008 revision of the IEEE 754 standard. This type is not widely supported by C compilers. It’s available as _Float16 type, if the compiler supports the Annex H of the C23 standard.

   Added in version 3.15.

3. Complex types (`Zf` and `Zd`) are available unconditionally, regardless on support for complex types (the Annex G of the C11 standard) by the C compiler. As specified in the C11 standard, each complex type is represented by a two-element C array containing, respectively, the real and imaginary parts.

   Added in version 3.15.

Ver también

The ctypes and struct modules, as well as third-party modules like numpy, use similar – but slightly different – type codes.

The actual representation of values is determined by the machine architecture (strictly speaking, by the C implementation). The actual size can be accessed through the `array.itemsize` attribute.

The module defines the following item:

array.typecodes

  A tuple with all available type codes.

  Distinto en la versión 3.15: The type changed from `str` to `tuple`.

El módulo define los siguientes tipos:

class array.array(typecode[, initializer])

  A new array whose items are restricted by typecode, and initialized from the optional initializer value, which must be a `bytes` or `bytearray` object, a Unicode string, or iterable over elements of the appropriate type.

  If given a `bytes` or `bytearray` object, the initializer is passed to the new array’s `frombytes()` method; if given a Unicode string, the initializer is passed to the `fromunicode()` method; otherwise, the initializer’s iterator is passed to the `extend()` method to add initial items to the array.

  Array objects support the ordinary mutable sequence operations of indexing, slicing, concatenation, and multiplication. When using slice assignment, the assigned value must be an array object with the same type code; in all other cases, `TypeError` is raised. Array objects also implement the buffer interface, and may be used wherever bytes-like objects are supported.

  Arrays are generic over the type of their contents.

  Lanza un evento de auditoría `array.__new__` con argumentos `typecode`, `initializer`.

  typecode

    El carácter typecode utilizado para crear el arreglo.

  itemsize

    La longitud en bytes de un elemento del arreglo en su representación interna.

  append(value, /)

    Append a new item with the specified value to the end of the array.

  buffer_info()

    Return a tuple `(address, length)` giving the current memory address and the length in elements of the buffer used to hold array’s contents. The size of the memory buffer in bytes can be computed as `array.buffer_info()[1] * array.itemsize`. This is occasionally useful when working with low-level (and inherently unsafe) I/O interfaces that require memory addresses, such as certain `ioctl()` operations. The returned numbers are valid as long as the array exists and no length-changing operations are applied to it.

    Nota

    Cuando utilizamos objetos tipo arreglo escritos en C o C++ (la única manera de utilizar esta información de forma más efectiva), tiene más sentido utilizar interfaces buffer que soporten objetos del tipo arreglo. Este método es mantenido con retro compatibilidad y tiene que ser evitado en el nuevo código. Las interfaces de buffer son documentadas en Protocolo búfer.

  byteswap()

    «Byteswap» all items of the array. This is only supported for values which are 1, 2, 4, 8 or 16 bytes in size; for other types of values, `RuntimeError` is raised. It is useful when reading data from a file written on a machine with a different byte order. Note, that for complex types the order of components (the real part, followed by imaginary part) is preserved.

  count(value, /)

    Return the number of occurrences of value in the array.

  extend(iterable, /)

    Añade los elementos del iterable al final del arreglo. Si el iterable es de otro arreglo, este debe ser exactamente del mismo tipo; si no, se lanza `TypeError`. Si el iterable no es un arreglo, este debe de ser un iterable y sus elementos deben ser del tipo correcto para ser añadidos al arreglo.

  frombytes(buffer, /)

    Appends items from the bytes-like object, interpreting its content as an array of machine values (as if it had been read from a file using the `fromfile()` method).

    Added in version 3.2: `fromstring()` is renamed to `frombytes()` for clarity.

  fromfile(f, n, /)

    Lee n elementos (como valores de máquina) del file object f y los añade al final del arreglo. Si hay menos de n elementos disponibles, se lanza `EOFError`, pero los elementos que estaban disponibles todavía se insertan en el arreglo.

  fromlist(list, /)

    Añade los elementos de la lista. Es equivalente a `for x in list: a.append(x)` excepto que si hay un error de tipo, el arreglo no se modifica.

  fromunicode(ustr, /)

    Extends this array with data from the given Unicode string. The array must have type code `'w'`; otherwise a `ValueError` is raised. Use `array.frombytes(unicodestring.encode(enc))` to append Unicode data to an array of some other type.

  index(value[, start[, stop]])

    Return the smallest i such that i is the index of the first occurrence of value in the array. The optional arguments start and stop can be specified to search for value within a subsection of the array. Raise `ValueError` if value is not found.

    Distinto en la versión 3.10: Se agregaron parámetros opcionales start y stop.

  insert(index, value, /)

    Insert a new item value in the array before position index. Negative values are treated as being relative to the end of the array.

  pop(index=-1, /)

    Elimina el elemento con índice i del arreglo y lo retorna. El argumento opcional por defecto es `-1`, en caso de utilizar el argumento por defecto el ultimo elemento es eliminado y retornado.

  remove(value, /)

    Remove the first occurrence of value from the array.

  clear()

    Remove all elements from the array.

    Added in version 3.13.

  reverse()

    Invierte el orden de los elementos en el arreglo.

  tobytes()

    Convierte el arreglo en un arreglo de valores máquina y retorna una representación en formato de bytes (la misma secuencia de bytes que se deben escribir en un fichero por el método `tofile()`.)

    Added in version 3.2: `tostring()` is renamed to `tobytes()` for clarity.

  tofile(f, /)

    Escribe todos los elementos (incluido elementos máquina) a el file object f.

  tolist()

    Convierte el arreglo a una lista ordinaria con los mismos elementos.

  tounicode()

    Convert the array to a Unicode string. The array must have a type `'w'`; otherwise a `ValueError` is raised. Use `array.tobytes().decode(enc)` to obtain a Unicode string from an array of some other type.

The string representation of array objects has the form `array(typecode, initializer)`. The initializer is omitted if the array is empty, otherwise it is a Unicode string if the typecode is `'w'`, otherwise it is a list of numbers. The string representation is guaranteed to be able to be converted back to an array with the same type and value using `eval()`, so long as the `array` class has been imported using `from array import array`. Variables `inf` and `nan` must also be defined if it contains corresponding floating-point values. Examples:

    array('l')
    array('w', 'hello \u2641')
    array('l', [1, 2, 3, 4, 5])
    array('d', [1.0, 2.0, 3.14, -inf, nan])

Ver también

Módulo `struct`

  Empaquetado y desempaquetado de datos binarios heterogéneos.

NumPy

  El paquete NumPy define otro tipo de arreglo.