How can I move a item in a numpy array?

Question

I have a numpy array -
['L', 'London', 'M', 'Moscow', 'NYC', 'Paris', 'nan']

I want 'nan' to be first, like so:
['nan', 'L', 'London', 'M', 'Moscow', 'NYC', 'Paris']

How can I do that?

Andrej Kesely · Answer

If you want to use numpy, you can use numpy.roll:
a = np.array(['L', 'London', 'M', 'Moscow', 'NYC', 'Paris', 'nan'])

a = np.roll(a, 1)

print(a)

Prints:
['nan' 'L' 'London' 'M' 'Moscow' 'NYC' 'Paris']

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