NumPy | floor method
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Numpy's floor(~)
method returns the floor for each value in the input array. See examples below for clarification.
Parameters
1. a
| array-like
The input array.
2. out
| Numpy array
| optional
Instead of creating a new array, you can place the computed result into the array specified by out
.
3. where
| array
of boolean
| optional
Values that are flagged as False will be ignored, that is, their original value will be uninitialized. If you specified the out parameter, the behavior is slightly different - the original value will be kept intact. Since this is a source of confusion for many, check examples below.
Return value
If a
is a scalar, then a scalar is returned. Otherwise, a Numpy array is returned.
Examples
Basic usage
np.floor([-3.2, -1.7, 1.5, 5.7])
array([-4., -2., 1., 5.])
Specifying an output array
a = np.zeros(3)np.floor([-3.2, -1.7, 1.5], out=a)a
array([-4., -2., 1.])
Specifying a boolean mask
np.floor([-3.2, -1.7, 1.5], where=[False, True, False])
array([3454., -2., 1867.])
Here, only the second number was used for calculation since it has a corresponding boolean of True
in the mask. You should notice how the values with False
yielded strange results - in fact, you should disregard them because they are uninitialized numbers that are of no practical use.
Now, if you specified the out
parameter, instead of uninitalized values, the original values will be left intact:
a = np.zeros(3)np.floor([-3.2, -1.7, 1.5], out=a, where=[False, True, False])a
array([ 0., -2., 0.])