# Convert ndarray from float64 to integer

55

I've got an `ndarray` in python with a `dtype` of `float64`. I'd like to convert the array to be an array of integers. How should I do this?

`int()` won't work, as it says it can't convert it to a scalar. Changing the `dtype` field itself obviously doesn't work, as the actual bytes haven't changed. I can't seem to find anything on Google or in the documentation - what's the best way to do this?

This question is tagged with `python` `numpy` `scipy`

~ Asked on 2012-01-13 18:46:48

### The Best Answer is

73

Use `.astype`.

``````>>> a = numpy.array([1, 2, 3, 4], dtype=numpy.float64)
>>> a
array([ 1.,  2.,  3.,  4.])
>>> a.astype(numpy.int64)
array([1, 2, 3, 4])
``````

See the documentation for more options.

~ Answered on 2012-01-13 18:52:11

10

While `astype` is probably the "best" option there are several other ways to convert it to an integer array. I'm using this `arr` in the following examples:

``````>>> import numpy as np
>>> arr = np.array([1,2,3,4], dtype=float)
>>> arr
array([ 1.,  2.,  3.,  4.])
``````

## The `int*` functions from NumPy

``````>>> np.int64(arr)
array([1, 2, 3, 4])

>>> np.int_(arr)
array([1, 2, 3, 4])
``````

## The NumPy `*array` functions themselves:

``````>>> np.array(arr, dtype=int)
array([1, 2, 3, 4])

>>> np.asarray(arr, dtype=int)
array([1, 2, 3, 4])

>>> np.asanyarray(arr, dtype=int)
array([1, 2, 3, 4])
``````

## The `astype` method (that was already mentioned but for completeness sake):

``````>>> arr.astype(int)
array([1, 2, 3, 4])
``````

Note that passing `int` as dtype to `astype` or `array` will default to a default integer type that depends on your platform. For example on Windows it will be `int32`, on 64bit Linux with 64bit Python it's `int64`. If you need a specific integer type and want to avoid the platform "ambiguity" you should use the corresponding NumPy types like `np.int32` or `np.int64`.

~ Answered on 2017-09-24 20:01:25