python: converting an numpy array data type from int64 to int

Question

I am somewhat new to python and I am using python modules in another program (ABAQUS). The question, however, is completely python related.

In the program, I need to create an array of integers. This array will later be used as an input in a function defined in ABAQUS. The problem is to do with the data type of the integers. In the array, the integers have data type 'int64'. However, I am getting the following error when I input the array to the desired function:

"Only INT, FLOAT and DOUBLE supported by the ABAQUS interface (use multiarray with typecode int if standard long is 64 bit)"

I do not need assistance with ABAQUS. If i convert the data type to 'int' in python, that would suffice. I thought that I could simply use the int() function to convert the data type. This did not work. Any suggestions will be highly appreciated. Thank you all.

@Sebastian: That still leaves the data type as int64. It does work for changing the data type from int to float. But not for int64 to int. — Srikanth
– Srikanth, Commented Sep 28, 2012 at 23:55
That works perfectly well, thank you! I was typing just ".astype(int)". I didn't realize "int" would give the platform dependent data type. Thanks again! — Srikanth
– Srikanth, Commented Sep 29, 2012 at 0:09
correct answer, per stackoverflow.com/questions/9452775/… is: ``` a.item() ``` — Hugh Perkins
– Hugh Perkins, Commented Aug 31, 2016 at 22:45

bigonazzi · Accepted Answer · 2020-04-16 18:49:51Z

42

numpy.ndarray.tolist will do it:

a.tolist()

If your data is a pandas series you can call their tolist wrapper with the same result.

answered Apr 16, 2020 at 18:49

bigonazzi

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Community · Accepted Answer · 2017-11-27 14:35:50Z

28

@J.F. Sebastian's answer:

a.astype(numpy.int32)

edited Nov 27, 2017 at 14:35

CommunityBot

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answered Feb 13, 2015 at 15:05

Srikanth

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1 Comment

Hari Over a year ago

This will work when passing the array to a function. In case, you want to change the type of the array, you need to assign to the array: a = a.astype(...)

Frank Freeman · Accepted Answer · 2018-03-23 03:05:22Z

3

Use the item() method for numpy.int64 object, as Mike T's answer in another similar question explained.

Official documentation is here: https://docs.scipy.org/doc/numpy-dev/reference/generated/numpy.chararray.item.html#numpy.chararray.item

answered Mar 23, 2018 at 3:05

Frank Freeman

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sarema · Accepted Answer · 2022-01-19 13:33:20Z

-1

In the end, if you convert an list of int64 values to int with numpy, you will have a numpy value (int64, int32, etc). In case you want a regular int (not numpy int), I found a way which is working. You will convert it to string, and then convert to list! enjoy...

import ast

a = ast.literal_eval(str(a))

edited Jan 19, 2022 at 13:33

sarema

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answered Jan 19, 2022 at 11:33

bardia rafieian

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anothernode · Accepted Answer · 2018-05-10 11:19:30Z

-6

If it's a pandas serise, you can first convert it to Dataframe, then use df.to_dict(), then the numpy.int64 will convert to int

In [1]: import pandas as pd

In [2]: import numpy as np

In [3]: df = pd.DataFrame(np.random.randint(5,size=(3,4)),
index=np.arange(3))

In [4]: type(df[0][0])

Out[4]: numpy.int64

In [5]: dict_of_df = df.to_dict()

In [6]: type(dict_of_df[0][0])

Out[6]: int

edited May 10, 2018 at 11:19

anothernode

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answered May 10, 2018 at 9:30

Charles q

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