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Add Numpy array into other Numpy array

asked 2013-07-27 04:21:42 -0500

mresimulator gravatar image

updated 2013-07-27 04:35:16 -0500

Hi experts!!

My code starts with a empty array (POPOPO=np.array([])).

In the next lines, np.array are created (L1, L2, ...). How can it add this new-created-arrays into POPOPO in order to obtain the array POPOPO= [[L1],[L2],...]? Its important to note that L1, L2,.... have different lenght.

Waiting for your answers.

Thanks in advance!

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Hello mresimulator, what type of arrays are the L1, L2,.. are they one-dimensional? btw, did you solve the problem already?

jack77 gravatar imagejack77 ( 2013-07-27 13:19:27 -0500 )edit

what did you tried so far to fill the POPOPO array?

jack77 gravatar imagejack77 ( 2013-07-27 14:01:04 -0500 )edit

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answered 2013-08-01 09:36:01 -0500

jack77 gravatar image

updated 2013-08-01 09:39:32 -0500


I do not know, if this construction is useful, but you could do the following:

 import numpy as np

 L1 = np.array( [1,2] )                         
 L2 = np.array( [1,2,3] )
 L3 = np.array( [3,2,2,3] )

 L = np.array( [L1, L2, L3], dtype=object )

 L[0] # will return array([1, 2])

if the number of the basic arrays are not known or is variable,
you could compose a command string and then use

count = 3
cmdstr = "L = np.array(["
for i in range(1, count):   cmdstr = cmdstr+ 'L'+str(i)+','
cmdstr = cmdstr+ 'L'+str(count)
cmdstr = cmdstr+"], dtype=object)"
cmdstr # : 'L = np.array([L1,L2,L3], dtype=object)'

exec(cmdstr) # L will be = array([[1 2], [1 2 3], [3 2 2 3]], dtype=object)

Remark: it did'nt work neither with np.concatenate nor with np.append

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Asked: 2013-07-27 04:21:42 -0500

Seen: 187 times

Last updated: Aug 01 '13