CODEWITHSUNDEEP
pythonarrayspython-3.xnumpy
Aventinus
Aventinus

Reputation: 1382

How do you call the element of position X in an numpy array?

import numpy as np

S = np.array(l)
for i in range(1, l):
    random_int = randint(0, 1)
    np.append(S, random_int)

I create a numpy array of size l and and fill it with zeros and ones. Let's say I want to print the third element of the array. How do I do that?

If I type 

print(S[2])

I get the following error: 

IndexError: too many indices for array

Upvotes: 1

Views: 949

Answers (3)

P. Camilleri
P. Camilleri

Reputation: 13218

First, S = np.array(l) does not result in an array of length l, but with a length 1 array whose only entry is l. So you can replace this line with S = np.zeros(l) (creating an array of length l full of zeros. Then, in your for loop, you must do:

for i in range l:
   S[i] = randint(0, 1)

This is just to point out your mistakes. As @Fabio said, you can do this in one line.

Upvotes: 1

Fabio Lamanna
Fabio Lamanna

Reputation: 21562

I would simply do in this way to generate L random numbers between 0 and 1:

L = 10
S = np.random.random_integers(0,1,L)
print S
print S[2]

returns:

[1 0 0 1 0 0 1 1 0 1]
0

Upvotes: 2

gtlambert
gtlambert

Reputation: 11961

np.append(S, random_int) appends random_int to a copy of the array S. You need to use S = np.append(S, random_int) in your for loop.

Example

import numpy as np
from random import randint

l = 5
S = np.array(l)
for i in range(1, l):
    random_int = randint(0, 1)
    S = np.append(S, random_int)

print(S)
print(S[2])

Output

[5 1 1 0 1]
1

Upvotes: 1

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