numpy array append is not working

Question

i am trying to append in numpy array.it does not showing any error but not appending the values in the array. i can't understand what's the reason.

ind=[]
ind=np.array(ind)
ind

out:array([], dtype=float64)
rand_num
out:0.2581020651429914

for i in T_Yk:
    print i,rand_num,i>=rand_num
    if i>=rand_num:
        np.append(ind,i)


0.841407208505 0.258102065143 True
0.544017164891 0.258102065143 True
0.847014100035 0.258102065143 True
0.837888398913 0.258102065143 True
0.602345432651 0.258102065143 True
0.758088894007 0.258102065143 True
0.875552313712 0.258102065143 True
0.566129640396 0.258102065143 True
0.398095901072 0.258102065143 True
0.708554596955 0.258102065143 True
0.308165627166 0.258102065143 True
0.716732072072 0.258102065143 True
0.760848001298 0.258102065143 True
0.307696603977 0.258102065143 True
0.574524448748 0.258102065143 True
0.608537650411 0.258102065143 True
0.661614576393 0.258102065143 True
0.358783413082 0.258102065143 True
0.396823316883 0.258102065143 True
0.867563492221 0.258102065143 True
0.520237352281 0.258102065143 True
0.866000916749 0.258102065143 True
0.851035162881 0.258102065143 True
0.566755675099 0.258102065143 True
0.687814928058 0.258102065143 True
0.787882814547 0.258102065143 True
0.8790451058 0.258102065143 True
0.538294379248 0.258102065143 True
0.543694673875 0.258102065143 True

but when i print the array ind,it shows

array([], dtype=float64)

You did not read the np.append docs. It is better use list append, and do one catenated at end — hpaulj
– hpaulj, Commented Feb 18, 2018 at 2:29
Duplicate of: stackoverflow.com/questions/19646726/… (and many other questions); stackoverflow.com/questions/40961972/… — hpaulj
– hpaulj, Commented Feb 18, 2018 at 4:35

jpp · Accepted Answer · 2018-02-18 02:31:41Z

7

np.append, unlike list.append, is not an in-place operation.

Therefore, assign back to original pointer:

ind = np.append(ind, i)

edited Feb 18, 2018 at 2:31

jpp

166k37 gold badges301 silver badges362 bronze badges

answered Feb 18, 2018 at 2:12

Der Fänger im Roggen

2,0253 gold badges23 silver badges44 bronze badges

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

Collectives™ on Stack Overflow

numpy array append is not working

1 Answer 1

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Linked

Related