[Python] Error_message: The truth value of an array with more than one element is ambiguous....

I'm having a problem with my code: when I make a search in the i-th column of the matrix, I get the following error:

if grades[:,i]!=-3:

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

I have tried to read the older posts on this issue, but can't really relate to my problem

I am trying to program a grading function according to danish grading-scale

def computeFinalGrades(grades):
#looping over the leth of grades
for i in range(len(loopingrange)):
#checking if any grade in the i-th column is -3
if grades[:,i]==-3:
#if a grade is equal to -3 then the output variable gradesFinal is -3
gradesFinal = -3
else:
#looping over all grade columns that do not contain one or more grades of -3
for i in range(len(loopingrange)):
#Checking to see if any column only contains 1 grade
if (len(grades[:,i]) == 1):
# if a column only contains 1 grade - that is also the final grade
gradesFinal = grades[:,i]
#Checking to see if column contains more than 1 grade and those grades are not -3
elif (len(grades[:,i]) > 1):
#storing all the grades in a variable - in random order
unsortedgrades = grades[:,i]
#sorting all the grades from lowest to highest
sortedgrades1 = np.sort(unsortedgrades)
#slicing the lowest grade out using indexing
sortedgrades = sortedgrades1[1::]
#finding the final grade as the mean of the n-1 grades
gradesFinal = np.mean(sortedgrades)
return gradesFinal

Continue reading...