a.any() or a.all() for how to fix this

Question

I don't have any idea with this error,

import NumPy as np

X = np.array([[1,2,3],
              [4,5,100],
              [-1,2,100],
              [3,8,9232020]])
print(X)
print('\n Dimension of the array is:')
print(X.shape)

def getMax(X):
  this_max=X[0]
  for e in X:
    if e > this_max:
      this_max=e
  return this_max

x_max=getMax(X)
print('x_max',x_max)
print('x_max', np.max(X))

the error is "if e > this_max:", and it is telling me the truth value of an array with more than one element is ambiguous. Use a.any() or a.all(), I don't know how to fix it.

`this_max` is an array and `e` is an array (`X` is 2-dim): Do you actually want that? — Timus, Sep 27 '20 at 23:28
`e` is an array of values, so `e > this_max` is a nonsense comparison. — John Gordon, Sep 27 '20 at 23:33
In your loop `print(e)` and `print(e>this_max)`. How is the `if` supposed to behave with that value? — hpaulj, Sep 28 '20 at 00:51

score 0 · Answer 1 · answered Sep 27 '20 at 23:29

0

Each e represents a list in X, for example X[0] = [1,2,3]. I assume you want to iterate over each list in the array to find the max value of all lists in the array.

answered Sep 27 '20 at 23:29

Sebastian Peterlin

158
6

Timus · Accepted Answer · 2020-09-27T23:42:40.010

0

In your code this_max is an array and e is an array (X is 2-dim). I suggest you try:

def getMax(X):
  this_max=X[0][0]
  for x in X:
    for e in x:
      if e > this_max:
        this_max=e
  return this_max

edited Sep 27 '20 at 23:42

answered Sep 27 '20 at 23:30

Timus

10,974
5
14
28

a.any() or a.all() for how to fix this

2 Answers2