Adding a string value to the end of each value in a Numpy Array Python

Question

What would be a numpy function that goes through array a and then appends the endswidth to the end of each string in the a array.

Code:

a = np.array(["BTC", "ETH", "AUD", "DOGE"])
endswidth = "USD"

Expected output:

[BTCUSD, ETHUSD, AUDUSD, DOGE]

Andrej Kesely · Accepted Answer · 2021-05-07 20:34:51Z

2

a = np.array(["BTC", "ETH", "AUD", "DOGE"])
endswidth = "USD"

print(np.core.defchararray.add(a, endswidth))

Prints:

['BTCUSD' 'ETHUSD' 'AUDUSD' 'DOGEUSD']

EDIT: To replace a string:

print(np.core.defchararray.replace(a, "USD", ""))

As @hpulj stated in the comments, the short form:

np.char.add(...) 
np.char.replace(...)

answered May 7, 2021 at 20:17

Andrej Kesely

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2 Comments

if I wanted to remove "USD" instead of the .add what would I use because I tried subtract and remove dont work.

np.char.add for short.

Hadar · Accepted Answer · 2021-05-07 20:18:36Z

1

perhaps this brute force approach will help

np.array([item+endswidth for item in a])

answered May 7, 2021 at 20:18

Hadar

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For string operations this is just as good as the np.char.add. numpy does not implement its own fast string methods.