在Python中的函数中传递列表

Question

I want to create a function which will receive a list, check each element of it and return a new list. If the element is greater than 97, it will put 100 in the new list. Otherwise, it will add three to the number and put it in the new list. At the function I just pass the list. However, when I run it it doesn't return anything.

Here is how I send the list to the function:

res=bonus(mark)

Here is my function:

def bonus(mark):
    new=[]
    for i in range(1,31):
        if (mark[i-1]>97):
            new.append(100)
        else:
            new.append(mark[i-1]+3)
    return new

Answer 1

You need to declare the function before calling it.

For example:

mark = [1,97,3,4,98,6,99,8,9,0,1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0]

def bonus(mark):
    new=[]
    for i in range(1,31):
        if (mark[i-1]>97):
            new.append(100)
        else:
            new.append(mark[i-1]+3)
    return new

res=bonus(mark)

print(res)

outputs:

[4, 100, 6, 7, 100, 9, 100, 11, 12, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 3]

Answer 2

If you go through a list, do not use range(..) use for item in listname:

def bonus(mark):
    new=[]
    for item in mark:  # item will be each element of mark in order, no need to indexaccess
        if (item > 97):
            new.append(100)
        else:
            new.append(item + 3)
    return new

Or shorten it to a list comprehension:

mark = list(range(80,100))

def bonus(m):
    return [min(100,m+3) for m in mark] # add m+3, if > 100 (for 98,99,100) use 100.

print (mark)
print (bonus(mark))

Output:

[80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99]
[83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 100, 100]