Python, Sort Array With Respect To A Sub-array
I have the following array: master_array = [[1. 2. 3. 4. 5.] [9. 8. 4. 5. 1.]] I would like to sort the master_array with respect to the second sub-array so that t
Solution 1:
Convert list to numpy array
>>> import numpy as np
>>> master_array = [[1.,2.,3.,4.,5.], [9.,8.,4.,5.,1.]]
>>> n=np.array(master_array)
>>> n
array([[ 1., 2., 3., 4., 5.],
[ 9., 8., 4., 5., 1.]])
Assign index values for the second array so take n[1]
>>>temp=list(enumerate(n[1]))>>>temp
[(0, 9.0), (1, 8.0), (2, 4.0), (3, 5.0), (4, 1.0)]
sort the array with respect to array elements
>>>list1=sorted(temp,key=lambda x:x[1])>>>list1
[(4, 1.0), (2, 4.0), (3, 5.0), (1, 8.0), (0, 9.0)]
Take all the indexes from sorted result and store in a seperate array
>>>a=[i[0] for i in list1 ]>>>a
[4, 2, 3, 1, 0]
Use indexing of columns in numpy on the numpy array
>>> n[:,a]
array([[ 5., 3., 4., 2., 1.],
[ 1., 4., 5., 8., 9.]])
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