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.
Answer from bigonazzi on Stack Overflownumpy.ndarray.tolist will do it:
a.tolist()
If your data is a pandas series you can call their tolist wrapper with the same result.
@J.F. Sebastian's answer:
a.astype(numpy.int32)
python - Convert 2D float array to 2D int array in NumPy - Stack Overflow
python - Convert Numpy array with 'n' and 'y' into integer array of 0 and 1 - Data Science Stack Exchange
python - Converting numpy array values into integers - Stack Overflow
python - convert numpy array to integer array - Stack Overflow
Use the astype method.
>>> x = np.array([[1.0, 2.3], [1.3, 2.9]])
>>> x
array([[ 1. , 2.3],
[ 1.3, 2.9]])
>>> x.astype(int)
array([[1, 2],
[1, 2]])
Some numpy functions for how to control the rounding: rint, floor,trunc, ceil. depending how u wish to round the floats, up, down, or to the nearest int.
>>> x = np.array([[1.0,2.3],[1.3,2.9]])
>>> x
array([[ 1. , 2.3],
[ 1.3, 2.9]])
>>> y = np.trunc(x)
>>> y
array([[ 1., 2.],
[ 1., 2.]])
>>> z = np.ceil(x)
>>> z
array([[ 1., 3.],
[ 2., 3.]])
>>> t = np.floor(x)
>>> t
array([[ 1., 2.],
[ 1., 2.]])
>>> a = np.rint(x)
>>> a
array([[ 1., 2.],
[ 1., 3.]])
To make one of this in to int, or one of the other types in numpy, astype (as answered by BrenBern):
a.astype(int)
array([[1, 2],
[1, 3]])
>>> y.astype(int)
array([[1, 2],
[1, 2]])
It is quite trivial
(X=='y').astype(int)
Should do the trick. It simply converts your array to True or False according to your requirements and then astype will impose the required datatype. By default int will give you 1 for True and 0 for False.
You could use the following code:
X[X=='y'] = 1
X[X=='n'] = 0
This replaces the indexes of 'y' with 1 and of 'n' with 0.
Generally the X=='y' returns a Boolean array which contains True where the 'y' and False everywhere else and so on.
Make a sample array
In [206]: x=np.array([1e9, 2e10, 1e6])
In [207]: x
Out[207]: array([ 1.00000000e+09, 2.00000000e+10, 1.00000000e+06])
We can convert to ints - except notice that the largest one is too large the default int32
In [208]: x.astype(int)
Out[208]: array([ 1000000000, -2147483648, 1000000])
In [212]: x.astype(np.int64)
Out[212]: array([ 1000000000, 20000000000, 1000000], dtype=int64)
Writing a csv with the default format (float) (this is the default format regardless of the array dtype):
In [213]: np.savetxt('text.txt',x)
In [214]: cat text.txt
1.000000000000000000e+09
2.000000000000000000e+10
1.000000000000000000e+06
We can specify a format:
In [215]: np.savetxt('text.txt',x, fmt='%d')
In [216]: cat text.txt
1000000000
20000000000
1000000
Potentially there are 3 issues:
- integer v float in the array itself, it's
dtype - display or print of the array
- writing the array to a csv file
It is a printing option, see the documentation: printing options. Briefly stated: you need to use the suppress option when printing:
np.set_printoptions(suppress=True) # for small floating point.
np.set_printoptions(suppress=True, formatter={'all':lambda x: str(x)})
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.
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.
I have two arrays, im1 and im2. When I say im1>im2, I get an array corresponding to the piece-wise evaluation of that statement. What I want now is to convert those trues and falses into 1's and 0's. How might I go about that, other than the obvious nested for loop?