I have two arrays. Both are 1D. However, I am getting the following Value Error. Below is what I tried.
R=np.arange(30,50,1)
T=np.arange(70,90,1)
H=[]
if (T > 8) and (R>10):
H.append(0.5 * (T + 61. + (T - 68.) * 1.2 + R * 0.094))
else:
H.append(0 * 2)
ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()
Simple as that.
import numpy as np
R=np.arange(30,50,1)
T=np.arange(70,90,1)
H=[]
if (T > 8).all() and (R>10).all():
H.append(0.5 * (T + 61. + (T - 68.) * 1.2 + R * 0.094))
else:
H.append(0 * 2)
print(H)
Here is an explanation.
If you really just want to know if atleast one element falls under the condition you should use any().
Python struggled to compare the values in the lists T to number.
The error is raised on T > 8.
For Lists
all() to check if all items in the list are above value:all(x > value for x in list)
any() to check if any item in the list are above value:any(x > value for x in list)
For NumPy Array
NumPy array, this can be shortened to:T = np.array([1,2,3])
all(T > 8)
Fix
Fix to all:
H=[]
import numpy as np
T = np.array([30,34,56])
R = np.array([29,500,43])
if all(T > 8) and all(R > 10):
H.append(0.5 * (T + 61. + (T - 68.) * 1.2 + R * 0.094))
else:
H.append(0 * 2)
(T > 8).all(), etc.
all(T > 80 for T in T) and all (T > 80 for T in T). I got False for both cases..any()
all(T > 8) and all(R > 10) to check all values or any(T > 8) and any(R > 10) to check if any of the values is above thresholdLike the above answer states, you can use all or any. The fix using any is:
if any(t > value for t in T) and any(h > value for h in H):
H.append(0.5 * (T + 61. + (T - 68.) * 1.2 + R * 0.094))
else:
H.append(0 * 2)
The python interpreter needs 1 value at a time so that it can compare.
TandRso that your problem is reproducible