Python Iterating 2D Array, Return Array Value

Question

I have created a 2D 10x10 Array. using Numpy I want to iterate over the array as efficiently as possible.

However I would like to return the array values. essentially iterating over the 10x10 array 10 times and return a 1x10 array each time.

 import datetime
 import numpy as np
 import random

 start = datetime.datetime.now()
 a = np.random.uniform(low=-1, high=1, size=(10,10))
 print("Time :",datetime.datetime.now() - start)

 for x in np.nditer(a):
    print(x)

the result is as follows:

0.5738994777717537
0.24988408410910767
0.8391827831682657
0.0015975845830569213
0.54477459840569
0.14091622639476165
-0.36517132895234106
-0.06311125453484467
-0.6572544506539948

...

100 times

However I would expect the result to be:

[0.5738994777717537,
0.24988408410910767,
0.8391827831682657,
0.0015975845830569213,
0.54477459840569,
0.14091622639476165,
-0.36517132895234106,
-0.06311125453484467,
-0.6572544506539948],[...]

...

10 times

Any help would be appreciated!

Answer 1

To directly answer your question, this does exactly what you want:

import numpy as np
a = np.random.uniform(low=-1, high=1, size=(10,10))
print(','.join([str(list(x)) for x in a]))

This will print

[-0.2403881196886386, ... , 0.8518165986395723],[-0.2403881196886386, ... , 0.8518165986395723], ..., [-0.2403881196886386, ... , 0.8518165986395723]

The reason you're printing just the elements of the array is due to the way nditer works. nditer iterates over single elements, even at a multidimensional level, whereas you want to iterate over just the first dimension of the array. For that, for x in a: works as intended.

Edit

Here is a good link if you want to read up on how nditer works: https://docs.scipy.org/doc/numpy/reference/arrays.nditer.html#arrays-nditer