How to get first element from each dimension in a numpy ndarray?
import numpy
A = numpy.array([['a','b','c'],['d','e','f'],['g','h','i']])
Result should be:
Result = ['a','d','g']
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3 Answers
>>> import numpy
>>> A = numpy.array([['a','b','c'],['d','e','f'],['g','h','i']])
>>> A[:,0]
array(['a', 'd', 'g'],
dtype='|S1')
>>> A[...,0]
array(['a', 'd', 'g'],
dtype='|S1')
See Indexing (basic) - NumPy Manual , Indexing - NumPy Manual.
Comments
Did you try this?
list( A[:,0] )
Indexing a numpy array will normally return another Numpy array, so you will need the list constructor if you need a list.
1 Comment
2964502
please explain the meanings of A[:,0] @dsign
use the take function
import numpy
A = numpy.array([['a','b','c'],['d','e','f'],['g','h','i']])
print A.take((0,), 1)
2 Comments
2964502
what are the meanings of 0 and 1 in A.take?@lcfseth
Samy Arous
it means that you want to get the first element ((0,)) (you can specify that you want the first and the third for example) along the (1) first axis.