Dan - 6 months ago 41

Python Question

I am using Pandas (first time) to determine whether personnel meet prerequisites when it comes to course attendance. The code below returns the desired results however I am sure there are much better ways to achieve the same outcome.

The criteria to determine if you can undertake physics is as follows;

`(Math_A OR Math_B OR Math_C) AND (Eng_A OR Eng_B) AND NOT (Physics)`

My question is what efficiencies or alternate methods can be applied to achieve the task.

Reading up on nested queries and alike, I am not able to come up with a way to compare multiple queries in the one query. Ideally, I'd like to have one statement that checks if the person satisfies the prerequisites however I have failed at this so far.

`Emplid,Name,CourseId,CourseName`

123,David,P12,Mathematics A

123,David,P13,Mathematics B

123,David,P14,Mathematics C

123,David,P32,Engineering A

456,Sally,P33,Engineering B

789,Roger,P99,Physics

`import pandas as pd`

def physics_meets_prereqs():

df = pd.DataFrame({'Emplid':['123','123', '123', '123', '456', '789'],

'Name':['David','David','David','David','Sally','Roger'],

'CourseId':['P12','P13','P14','P32','P33','P99'],

'CourseName':['Mathematics A','Mathematics B','Mathematics C','Engineering A','Engineering B', 'Physics']

})

# Get datasets of individually completed courses

has_math = df.query('CourseId == "P12" or CourseId == "P13" or CourseId == "P14"')

has_eng = df.query('CourseId == "P32" or CourseId == "P33"')

has_physics = df.query('CourseId == "P99"')

# Get personnel who have completed math and engineering

has_math_and_eng = has_math[(has_math['Emplid'].isin(has_eng['Emplid']))]

# Remove personnel who have completed physics

has_math_and_eng_no_physics = has_math_and_eng[~(has_math_and_eng['Emplid'].isin(has_physics['Emplid']))]

print(has_math_and_eng_no_physics)

physics_meets_prereqs()

`CourseId CourseName Emplid Name`

0 P12 Mathematics A 123 David

1 P13 Mathematics B 123 David

2 P14 Mathematics C 123 David

The output is resulting in David being identified as meeting the prerequisites for the physics course. It does list him 3 times which I have not figured out how to limit as yet. The way I am achieving this though can definitely be improved.

Show me a list of people who have completed at least one of the maths courses, at least one of the engineering courses and have not yet completed the physics course.

Answer