Multiple conditions np.extract

Question

I have an array and want ot extract all entries which are in a specific range

x = np.array([1,2,3,4])
condition = x<=4 and x>1
x_sel = np.extract(condition,x)

But this does not work. I'm getting

ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

If I'm doing the same without the and and checking for example only one condition

x = np.array([1,2,3,4])
condition = x<=4 
x_sel = np.extract(condition,x)

everything works... Of courese I could just apply the procedure twice with one condition, but isn't there a solution to do this in one line?

Many thanks in advance

Did you try using `&` instead `and` ? – YesThatIsMyName May 30 '18 at 09:53 — YesThatIsMyName, May 30 '18 at 09:53

score 7 · Answer 1 · answered May 30 '18 at 10:01

7

You can use either this:

import numpy as np

x = np.array([1,2,3,4])
condition = (x <= 4) & (x > 1)
x_sel = np.extract(condition,x)
print(x_sel)
# [2 3 4]

Or this without extract:

x_sel = x[(x > 1) & (x <= 4)]

answered May 30 '18 at 10:01

Austin

score 4 · Accepted Answer · answered May 30 '18 at 09:55

4

This should work:

import numpy as np

x = np.array([1,2,3,4])
condition = (x<=4) & (x>1)
x_sel = np.extract(condition,x)

answered May 30 '18 at 09:55

Fourier

2 Answers2