Is there an easier way(pythonic) to write the following code?

Question

sigma_n = np.array([0.01, 0.1])

ls = np.array([0.1, 0.2])

for sigma_ni in sigma_n:
    for ls_i in ls:
        print("{},{}".format(sigma_ni, ls_i))

I was hoping to find out if there is any way I could print out the above in a pythonic way instead of 2 loops.

if you are printing, that's look good. You can use `itertools.product` so you can have just one loop. But that's essentially the same thing. — Quang Hoang, Mar 08 '21 at 17:01
2 for loops. If the arrays are large, it is certainly slow right? — Harshvardhan Uppaluru, Mar 08 '21 at 17:06
Thank you @QuangHoang. itertools.product helps for the next steps I will be working on. — Harshvardhan Uppaluru, Mar 08 '21 at 17:06
@HarshvardhanUppaluru **but you must do those two loops** if you want to print everything. There's no way around this. Again, what isn't **pythonic** about this? — juanpa.arrivillaga, Mar 08 '21 at 17:11
Reading through the comments - I have realized I am wrong. I am still at a learning stage and I thought there was an easier(I am using this term because I couldn't think of any other) way through loop through 2 arrays. That is why I used the term - pythonic — Harshvardhan Uppaluru, Mar 08 '21 at 17:16

score 1 · Answer 1 · answered Mar 08 '21 at 17:03

1

You can use itertools.product -

from itertools import product

items = product(sigma_n, ls)

for i in items:
    print(i)

answered Mar 08 '21 at 17:03

Akshay Sehgal

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Thank you! I think this could be the way forward. – Harshvardhan Uppaluru Mar 08 '21 at 17:05
Do note that the object returned is a generator object and you will have to explicitly iterate or convert it to a list `list(items)` to work on its items. – Akshay Sehgal Mar 08 '21 at 17:09
1

@HarshvardhanUppaluru it is important to understand, this still effectively does two nested loops – juanpa.arrivillaga Mar 08 '21 at 17:11
@juanpa.arrivillaga that is correct. – Akshay Sehgal Mar 08 '21 at 17:12
@AkshaySehgal to be pedantic, it doesn't return a generator, but it is an iterator – juanpa.arrivillaga Mar 08 '21 at 17:12
Thank you @juanpa.arrivillaga. – Harshvardhan Uppaluru Mar 08 '21 at 17:13
@juanpa.arrivillaga, are you sure? The documentation mentions -`product(A, B) returns the same as ((x,y) for x in A for y in B)`. – Akshay Sehgal Mar 08 '21 at 17:16
Yes, test it out yourself. `type(product(range(1))` – juanpa.arrivillaga Mar 08 '21 at 17:20
Ah yes i did that and it just returned the `itertools.product` class object. My question is, whether this class object is a generator or just an iterator. Let me check the source to figure it out. – Akshay Sehgal Mar 08 '21 at 18:37
@AkshaySehgal *generators are a type object*. If the type is not `generator` then it isn't a generator. All generators are iterators, not all iterators are generators. Generators have various additional methods, for example, `.close`, `.send` (since generators are also co-routines) and various attributes, like `.gi_running` – juanpa.arrivillaga Mar 09 '21 at 00:02
Ah ok, thanks for the clarification. – Akshay Sehgal Mar 09 '21 at 06:48

score 0 · Answer 2 · answered Mar 08 '21 at 17:04

0

Look like your printing meshgrid

print(np.meshgrid(sigma_n, ls)

[array([[0.01, 0.1 ],
       [0.01, 0.1 ]]), 
array([[0.1, 0.1],
       [0.2, 0.2]])]

answered Mar 08 '21 at 17:04

Kenan

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Is there an easier way(pythonic) to write the following code?

2 Answers2