What is NumPy RuntimeWarning: Mean of empty slice in Python?
The NumPy RuntimeWarning: Mean of empty slice in Python occurs when attempting to calculate the mean of an empty NumPy array slice. This warning is an indication that the code is trying to perform a mathematical operation on a subset of an array that has no elements. Understanding the reasons behind this warning is crucial for resolving the issue effectively.
Syntax:
Numpy Runtimewarning: Mean Of Empty Slice
Below is the reason why NumPy RuntimeWarning: Mean of empty slice occurs in Python:
- Empty Slicing
- Invalid Indexing
Empty Array
In this example, the code creates an empty NumPy array, and then attempts to calculate the mean of a slice with no elements, triggering a “RuntimeWarning: Mean Of Empty Slice” because there are no values to compute the mean from.
Python3
import numpy as np#defining the arrayempty_array = np.array([])np.mean(empty_array) |
Output
/usr/local/lib/python3.7/site-packages/numpy/core/fromnumeric.py:3441: RuntimeWarning: Mean of empty slice.
out=out, **kwargs)
/usr/local/lib/python3.7/site-packages/numpy/core/_methods.py:189: RuntimeWarning: invalid value encountered in double_scalars
ret = ret.dtype.type(ret / rcount)
Invalid Indexing
In this example, below code creates an empty slice with indices [5:2] from a NumPy array, and then attempts to calculate the mean of this empty slice, resulting in a “RuntimeWarning: Mean Of Empty Slice” since there are no elements in the slice.
Python3
import numpy as npdata = np.array([1, 2, 3, 4, 5])empty_slice = data[5:2] output = np.mean(empty_slice) print(output) |
Output
packages/numpy/core/fromnumeric.py:3504: RuntimeWarning: Mean of empty slice.
return _methods._mean(a, axis=axis, dtype=dtype,
/usr/local/lib/python3.10/dist-packages/numpy/core/_methods.py:129: RuntimeWarning: invalid value encountered in scalar divide
ret = ret.dtype.type(ret / rcount)
NumPy RuntimeWarning: Mean of empty slice in Python
Here, we will see how to fix “Numpy Runtimewarning: Mean Of Empty Slice” in Python. In this article, we will see the reasons for it’s occurrence and also the solution of NumPy RuntimeWarning: Mean of empty slice in Python.
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