Remove punctuation from numpy string arrays

Question

The string package is useful for stripping punctuation from individual strings as demonstrated below:

import string
stripPunct = str.maketrans('', '', string.punctuation)

word = 'foo.bar.baz'

word.translate(stripPunct)

Output: 'foobarbaz'

But what is the method to apply this exact same method to every string in a numpy array of strings?

myArr =   np.array(['foo.bar.baz', 'foo.bar.baz', 'foo.bar.baz'], dtype='<U15')


myArr.translate(stripPunct)
AttributeError: 'numpy.ndarray' object has no attribute 'translate'

Is np.array -> list -> map or list comprehension -> np.array an option for you? — Jan Stránský
– Jan Stránský, Commented Sep 3, 2020 at 21:16
Iterate? res = [words.translate(stripPunct) for words in myArr] — wp78de
– wp78de, Commented Sep 3, 2020 at 21:19

neuops · Accepted Answer · 2020-09-08 20:04:26Z

2

import string
import numpy as np

stripPunct = str.maketrans('', '', string.punctuation)

myArr =  np.array(['foo.bar.baz', 'foo.bar.baz', 'foo.bar.baz'])
# works for 'any.string.inputted'
new = np.array([i.translate(stripPunct) for i in myArr])

Output:

array(['foobarbaz', 'foobarbaz', 'foobarbaz'])

edited Sep 8, 2020 at 20:04

answered Sep 3, 2020 at 21:19

neuops

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Comments

fusion · Accepted Answer · 2020-09-03 21:27:48Z

1

You can use np.vectorize to make a vectorized function.


stripPunct=str.maketrans('', '', string.punctuation)
vecTrans=np.vectorize(lambda x:x.translate(stripPunct))
myArr=np.array(['foo.bar.baz', 'foo.bar.baz', 'foo.bar.baz'], dtype='<U15')

vecTrans(myArr)

>>>return: array(['foobarbaz', 'foobarbaz', 'foobarbaz'], dtype='<U9')

answered Sep 3, 2020 at 21:27

fusion

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1 Comment

hpaulj Over a year ago

Is that any better than the list comprehension suggestion?

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