How can I append an array in NumPy using an input function?

Question

I'm trying to work on a program that allows users to add numbers to an array and then perform mathematical operations on the arrays via NumPy but I'm having trouble working out how users can add numbers to the list.

I have a code that is a variation of the following:

list = np.array[(1, 2, 3)] 
list = np.append(int(input("Please add a number to the list:")))
print(list)

And I want the user to able to input "4" and have it show up at the end of the array like: [1, 2, 3, 4].

Never used NumPy before so I'm unsure as to how a lot of it works. Is there an alternative method I should be using?

Did you spend any time reading the docs for np.append? Or did you just assume it behaves just like list append? Either way, I discourage its use. List append is better - safer and faster. — hpaulj
– hpaulj, Commented Jun 24, 2020 at 15:44

Ehsan · Accepted Answer · 2020-06-24 10:43:06Z

1

Better idea is to append to list and then convert to numpy array. Appending to numpy array is slower:

list = [1, 2, 3] 
list.append(int(input("Please add a number to the list:")))
print(np.array(list))

answered Jun 24, 2020 at 10:43

Ehsan

12.5k2 gold badges24 silver badges36 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Narendra Prasath · Accepted Answer · 2020-06-24 09:38:12Z

0

You can try this:

np.append() works for adding elements

list = np.array([1, 2, 3])
## get the number from user
n = int(input("Please add a number to the list:"))
list = np.append(list, n)
list

output:

array([1, 2, 3, 4])

answered Jun 24, 2020 at 9:38

Narendra Prasath

1,5311 gold badge10 silver badges20 bronze badges

Comments

Pavan kumar · Accepted Answer · 2020-06-24 09:54:29Z

0

import numpy as np
list = np.array([1, 2, 3])
list = np.append(list, int(input("Please add a number to the list:")))
print(list)

The output will be like this [1 2 3 4]

and you can directly do any arithmatic operation on that array like

    list*12
    list+20
    list*[2,4,5,5]  #array multiplication

numpy docs
let me know is this helpful for you

edited Jun 24, 2020 at 9:54

answered Jun 24, 2020 at 9:48

Pavan kumar

5154 silver badges19 bronze badges

Collectives™ on Stack Overflow

How can I append an array in NumPy using an input function?

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related