numpy.insert


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This function inserts values in the input array along the given axis and before the given index. If the type of values is converted to be inserted, it is different from the input array. Insertion is not done in place and the function returns a new array. Also, if the axis is not mentioned, the input array is flattened.

The insert() function takes the following parameters −

numpy.insert(arr, obj, values, axis)

Where,

Sr.No. Parameter & Description
1

arr

Input array

2

obj

The index before which insertion is to be made

3

values

The array of values to be inserted

4

axis

The axis along which to insert. If not given, the input array is flattened

Example

import numpy as np 
a = np.array([[1,2],[3,4],[5,6]]) 

print 'First array:' 
print a 
print '\n'  

print 'Axis parameter not passed. The input array is flattened before insertion.'
print np.insert(a,3,[11,12]) 
print '\n'  
print 'Axis parameter passed. The values array is broadcast to match input array.'

print 'Broadcast along axis 0:' 
print np.insert(a,1,[11],axis = 0) 
print '\n'  

print 'Broadcast along axis 1:' 
print np.insert(a,1,11,axis = 1)

Its output would be as follows −

First array:
[[1 2]
 [3 4]
 [5 6]]

Axis parameter not passed. The input array is flattened before insertion.
[ 1 2 3 11 12 4 5 6]

Axis parameter passed. The values array is broadcast to match input array.
Broadcast along axis 0:
[[ 1 2]
 [11 11]
 [ 3 4]
 [ 5 6]]

Broadcast along axis 1:
[[ 1 11 2]
 [ 3 11 4]
 [ 5 11 6]]
numpy_array_manipulation.htm
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