`numpy:promote_types`

Signature

built-in promote_types ( type1 , type2 , / )

Summary

Returns the data type with the smallest size and smallest scalar kind to which both type1 and type2 may be safely cast. The returned data type is always considered "canonical", this mainly means that the promoted dtype will always be in native byte order.

Extended Summary

This function is symmetric, but rarely associative.

Parameters

type1 : dtype or dtype specifier: First data type.
type2 : dtype or dtype specifier: Second data type.

Returns

out : dtype: The promoted data type.

Notes

Please see numpy.result_type for additional information about promotion.

Starting in NumPy 1.9, promote_types function now returns a valid string length when given an integer or float dtype as one argument and a string dtype as another argument. Previously it always returned the input string dtype, even if it wasn't long enough to store the max integer/float value converted to a string.

NumPy now supports promotion for more structured dtypes. It will now remove unnecessary padding from a structure dtype and promote included fields individually.

Examples

import numpy as np
np.promote_types('f4', 'f8')

✓

np.promote_types('i8', 'f4')

✓

np.promote_types('>i8', '<c8')

✓

np.promote_types('i4', 'S8')

✓

An example of a non-associative case:

p = np.promote_types
p('S', p('i1', 'u1'))
p(p('S', 'i1'), 'u1')

`numpy:promote_types`

Signature

Summary

Extended Summary

Parameters

Returns

Notes

Examples

See also

Aliases

Referenced by

This package