Check if list of keys exist in dictionary [duplicate]

Question

I have a dictionary that looks like that:

grades = {         'alex' : 11,         'bob'  : 10,         'john' : 14,         'peter': 7        } 

and a list of names students = ('alex', 'john')

I need to check that all the names in students exist as keys in grades dict.

grades can have more names, but all the names in students should be in grades

There must be a straightforward way to do it, but i'm still new to python and can't figure it out. tried if students in grades, didn't work.

In the actual cases, the lists will be much bigger.

Answer 1

Use all():

if all(name in grades for name in students):     # whatever 

Answer 2

>>> grades = {         'alex' : 11,         'bob'  : 10,         'john' : 14,         'peter': 7 } >>> names = ('alex', 'john') >>> set(names).issubset(grades) True >>> names = ('ben', 'tom') >>> set(names).issubset(grades) False 

Calling it class is invalid so I changed it to names.