AttributeError: 'numpy.ndarray' object has no attribute 'median'
numpy, python
Solution
Although `numpy.ndarray` has a `mean`, `max`, `std` etc. method, it does not have a `median` method. For a list of all methods available for an `ndarray`, see the `numpy` documentation for `ndarray`.
It is available as a function that takes the array as an argument:
>>> import numpy as np
>>> a = np.array([1,2,3,4,5,6,7,8,9,10])
>>> np.median(a)
5.5
As you will see in the documentation for `ndarray.mean`, `ndarray.mean` and `np.mean` are "equivalent functions," so this is just a matter of semantics.
Problem
I can perform a number of statistics on a numpy array but "median" returns an attribute error. When I do a "dir(np)" I do see the median method listed. ``` (newpy2) 7831c1c083a2:src scaldara$ python Python 2.7.12 |Continuum Analytics, Inc.| (default, Jul 2 2016, 17:43:17) [GCC 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.11.00)] on darwin Type "help", "copyright", "credits" or "license" for more information. Anaconda is brought to you by Continuum Analytics. Please check out: http://continuum.io/thanks and https://anaconda.org >>> import numpy as np >>> print(np.version.version) 1.11.2 >>> a = np.array([1,2,3,4,5,6,7,8,9,10]) >>> print(a) [ 1 2 3 4 5 6 7 8 9 10] >>> print(a.min()) 1 >>> print(a.max()) 10 >>> print(a.mean()) 5.5 >>> print(a.std()) 2.87228132327 >>> print(a.median()) Traceback (most recent call last): File "<stdin>", line 1, in <module> AttributeError: 'numpy.ndarray' object has no attribute 'median' >>> ```