Unpack NumPy array by column
You can unpack the transpose of the array in order to use the columns for your function arguments:
my_func(*arr.T)
Here's a simple example:
>>> x = np.arange(15).reshape(5, 3)array([[ 0, 5, 10], [ 1, 6, 11], [ 2, 7, 12], [ 3, 8, 13], [ 4, 9, 14]])
Let's write a function to add the columns together (normally done with x.sum(axis=1)
in NumPy):
def add_cols(a, b, c): return a+b+c
Then we have:
>>> add_cols(*x.T)array([15, 18, 21, 24, 27])
NumPy arrays will be unpacked along the first dimension, hence the need to transpose the array.
numpy.split splits an array into multiple sub-arrays. In your case, indices_or_sections
is 3 since you have 3 columns, and axis = 1
since we're splitting by column.
my_func(numpy.split(array, 3, 1))
I guess numpy.split
will not suffice in the future. Instead, it should be
my_func(tuple(numpy.split(array, 3, 1)))
Currently, python prints the following warning:
FutureWarning: Using a non-tuple sequence for multidimensional indexing is deprecated; use
arr[tuple(seq)]
instead ofarr[seq]
. In the future this will be interpreted as an array index,arr[np.array(seq)]
, which will result either in an error or a different result.