Why can't I convert floats in an array into integers?

Question

I want to convert the elements(float) into integer, but it seems not working.

#get an array from a matrix
pre_dataY = data[:, -1]
print(pre_dataY)
# float to integer
for i in range(len(pre_dataY):
    pre_dataY[i]=int(pre_dataY[i]) 
print(pre_dataY)

however, the output is :

[ 3.  2.  9. ...,  7.  5.  5.]

[ 3.  2.  9. ...,  7.  5.  5.]

I don't see why that is?

`numpy` arrays preserve the type. Do `new_array=pre_dataY.astype(np.int)` instead. — Thomas Kühn, Dec 14 '17 at 10:12
Possible duplicate of [In-place type conversion of a NumPy array](https://stackoverflow.com/questions/4389517/in-place-type-conversion-of-a-numpy-array) — Thomas Kühn, Dec 14 '17 at 10:15

Gsk · Answer 1 · 2017-12-14T10:37:18.767

0

use mapping:

print map(int, pre_dataY)

Mapping create a new list with your values

edited Dec 14 '17 at 10:37

answered Dec 14 '17 at 10:24

Gsk

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But `pre_dataY` is an array, and presumably the OP wants it to remain so. If it started as a list, the inplace change would have worked. – hpaulj Dec 14 '17 at 18:16

score -1 · Answer 2 · edited Dec 14 '17 at 11:29

-1

You are missing a closing parens in the loop:

You have:

for i in range(len(pre_dataY):

It should be:

for i in range(len(pre_dataY)):

edited Dec 14 '17 at 11:29

jwpfox

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answered Dec 14 '17 at 10:21

Rudradev Pal

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This answer looks OK but could use some more details and an explanation. – Rolf ツ Dec 14 '17 at 11:07

Why can't I convert floats in an array into integers?

2 Answers2