如果列表中有整数 k 和 n，则返回 True 的函数？

Question

Very new to python... If I give a list that has two integers n and k, the function should return Boolean True. K has to be in the list the number of n times. For example, if I call matchingValues([1, 2, 1, 4, 1, 1], 1, 4) should return True since 1 is in the list 4 times. I'm guessing I have to use the .count() option but not sure how to write it... Wish I could give more code but unfortunately I am very lost

    def matchingValues(aList,n,k):

Answer 1

Better than a solution involving len() is to use the .count() method for lists. It takes an argument, and returns the number of times that argument appears in the list that it is called on.

Answer 2

What you want to do is define a variable which counts how many times n is in the list

found = 0

and then, iterate over your list with a loop

for x in range(0, len(aList)):
    if aList[x] == n:
        found += 1
return(found == k)

This is, however, if you want to avoid using the count function:

return(aList.count(n)==k)

Using the manual, hand-written loop will allow you to exit the loop as soon as you know there are k n s in the list, if you want the loop to work like that (however, I have not provided that code. I have only written exactly what count does)

If you want there to be AT LEAST k n s in aList , this would work for you

found = 0
for x in range(0, len(aList)):
    if aList[x] == n:
        found += 1
        if found == k:
            return True
return False