python-arrayx

An enhancement to Python's array class with instantiation conveniences

Note that this is not yet a distribution package and is not yet versioned.

If you want to use this code today, you must simply copy the code into your project.

Requirements

Python 3.x

##Overview The array.array class in the Python standard linrary has a single means of specifying the size and signedness of the items it will contain which is to supply a single-characer typecode string. Each typecode corresponds to a C-language data type, and many of those types have different sizes depending on the platform. As a result, it can be difficult to create an array of integer items with a specific platform-independent size.

The arrayx.Array class is a subclass of array.array that supports the initialization using any of the same typecodes that array.array accepts but can also have its item properties specified by any of the following methods.

Fixed-Width Integer Typecode

A 2-letter typecode of "i1", "u1" "i2", "u2", "i4", "u4", "i8", or "u8". The first letter indicates whether item values are signed or not ("i" for signed integer or "u" for unsigned integer) and the number is the item size in bytes.

Integer Size and Optional Signedness

An integer value for the integer-type item size (signed by default) and an optional is_signed argument to specify signed or unsigned.

Minimum and Maximum Value Bounds via IntBounds Instance

An instance of arrayx.IntBounds may be given to indicate integer items with the smallest itemsize that can represent any value from its minval through (and including) its maxval. If either the signed or unsigned type of that size qualifies, then the signed type is used. If only the signed type of that size qualifies, then that is used.

Examples

# Unsigned short (2-byte) items. Same as `array.array('H')`.
arrayx.Array('H')

# Float-type items. Same as `array.array('f')`.
arrayx.Array('f')

# Signed 4-byte integer items (typecode 'i' or 'l' depending on platform)
arrayx.Array('i4')

# Unsigned 8-byte integer items.
arrayx.Array(8, is_signed=False)

# Signed 2-byte integer items. Either of the following.
arrayx.Array(arrayx.IntBounds(0, 120)
arrayx.Array(arrayx.IntBounds(-1, 200)

# Unsigned 1-byte integer items.
arrayx.Array(arrayx.IntBounds(0, 200)

Future

In the future, this library will also provide efficient enhanced initialization of array contents such as specifying a size and value with which to initially fill the items.