How can I convert a numpy array of float type into a numpy array of int type?

Question

I have the following source code:

npW_x = np.array(my_np_array)
npW_round_111 = np.around(npW_x, decimals=0)
sum_x_111 = np.sum(npW_round_111, axis=1)

np.savetxt("file1.txt", sum_x_111)

File output

3.200000000000000000e+01
5.500000000000000000e+01
3.300000000000000000e+01
4.900000000000000000e+01
5.200000000000000000e+01
5.500000000000000000e+01
3.800000000000000000e+01
5.200000000000000000e+01
5.100000000000000000e+01
3.100000000000000000e+01
3.100000000000000000e+01
3.200000000000000000e+01
5.100000000000000000e+01
... ... ... ... ... ...

The expected output is as follows:

3
6
3
5
5
6
4
5
5
3
3
3
5
... ... ... ... ... ...

How can I do this?

You can supply the dtype of your choice - np.sum(npW_round_111, axis=1,dtype=np.int64) — Vaebhav
– Vaebhav, Commented Sep 20, 2021 at 5:54
I think you can use the astype(int) - stackoverflow.com/questions/10873824/… — nkacolz
– nkacolz, Commented Sep 20, 2021 at 5:55
Note, you're not going to get that "expected" output. 3.200000000000000000e+01 is 32.0, not 3.0. The e+01 means "times 10 to the 1st power". — user2357112
– user2357112, Commented Sep 20, 2021 at 6:01
Unduping because this isn't just a dtype issue. There is a dtype issue, but it's not the only issue - numpy.savetxt defaults to fmt='%.18e' even if you pass it an array of integer dtype. — user2357112
– user2357112, Commented Sep 20, 2021 at 6:03

hpaulj · Accepted Answer · 2021-09-20 06:37:30Z

1

In [385]: npW_x = np.random.rand(4,5)*10
     ...: npW_round_111 = np.around(npW_x, decimals=0)
     ...: sum_x_111 = np.sum(npW_round_111, axis=1)
     ...: 
In [386]: sum_x_111
Out[386]: array([38., 25., 24., 30.])

save with default fmt (Read and reread the np.savetxt docs!)

In [387]: np.savetxt('test',sum_x_111)
In [388]: cat test
3.800000000000000000e+01
2.500000000000000000e+01
2.400000000000000000e+01
3.000000000000000000e+01

save with int format:

In [389]: np.savetxt('test',sum_x_111, fmt='%10d')
In [390]: cat test
        38
        25
        24
        30

conversion in memory to int:

In [391]: In [391]: sum_x_111.astype(int)
Out[391]: array([38, 25, 24, 30])

answered Sep 20, 2021 at 6:37

hpaulj

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Comments

Vigneshwar Ravichandar · Accepted Answer · 2021-09-20 06:05:19Z

0

You can use astype() function for this

I'm considering npW_x to be the array which needs to be converted into int array.

npW_x = np.array(my_np_array)
npW_x = npW_x.astype('int32')

Now, it should be converted into an integer numpy array.

Edit:

I have added the full code, so that you can try

npW_x = np.array(my_np_array)
npW_x = npW_x.astype('int32')
sum_x_111 = np.sum(npW_x, axis=1)
np.savetxt("file1.txt", sum_x_111)

Hope it resolved your problem.

edited Sep 20, 2021 at 6:05

answered Sep 20, 2021 at 5:55

Vigneshwar Ravichandar

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4 Comments

user366312 Over a year ago

doesn't work...

Vigneshwar Ravichandar Over a year ago

May i know what error did you get?

user366312 Over a year ago

The file1.txt contains values with decimal points. E.g. 6.000000000000000000e+00 6.000000000000000000e+00, etc.

Vigneshwar Ravichandar Over a year ago

i have added the full code. do tell me if it didnt work

padu · Accepted Answer · 2021-09-20 06:09:34Z

0


arr = np.asarray([3.200000000000000000e+01,
5.500000000000000000e+01,
3.300000000000000000e+01,
4.900000000000000000e+01,
5.200000000000000000e+01,
5.500000000000000000e+01,
3.800000000000000000e+01,
5.200000000000000000e+01,
5.100000000000000000e+01,
3.100000000000000000e+01,
3.100000000000000000e+01,
3.200000000000000000e+01,
5.100000000000000000e+01])

arr

array([32. , 55. , 33. , 49. , 52. , 55. , 38. , 52. , 51. , 31. , 31. ,
       32. ,  5.1])

np.around(np.where(arr//10, arr/10, arr)).astype('int')

get

array([3, 6, 3, 5, 5, 6, 4, 5, 5, 3, 3, 3, 5])

edited Sep 20, 2021 at 6:09

answered Sep 20, 2021 at 5:56

padu

9098 silver badges12 bronze badges

3 Comments

user366312 Over a year ago

doesn't work...

padu Over a year ago

What is the error?

user366312 Over a year ago

The file1.txt contains values with decimal points. E.g. 6.000000000000000000e+00 6.000000000000000000e+00, etc.

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