Slice numpy array based on values of other array using more than 2 arguments

Question

Here's my current code:

a = np.array(['apples', 'pear', 'oranges', 'grapes', 'apples', 'banana'])
b = np.array([1,2,3,4,5,6])
my_list = ['apples', 'oranges', 'grapes']

How do I create a line of code that will return the following result:

result = np.array([1,3,4,5])

The method must use my_list as the basis for slicing array b based on array a. (It should work regardless of the length of my_list)

Thanks in advance!

So you don't want to include 5 for apples in your output too? — gtlambert
– gtlambert, Commented Jan 28, 2016 at 9:12
What if a = np.array(['oranges', 'apples', 'pear', 'grapes', 'apples', 'banana']). i.e. the items in a and not in the order of my_list? — Divakar
– Divakar, Commented Jan 28, 2016 at 9:21

gtlambert · Accepted Answer · 2016-01-28 09:18:22Z

1

You could slice using np.in1d():

In [15]: b[np.in1d(a, my_list)]
Out[15]: array([1, 3, 4, 5])

answered Jan 28, 2016 at 9:13

gtlambert

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