列表 python 的总和 + 从列表中删除字符串

Question

I have a problem where I need to take user input ie (Jack,10,10,9,10,10) with Jack being student name and the numbers are test scores. I need to find the average of those test scores and print them with the student name. This problem seems very straightforward put I get an output error that says:

>>> calcMarks()
Enter marks:Jack,10,10,9,10,10
Traceback (most recent call last):
File "<pyshell#32>", line 1, in <module>
calcMarks()
File "xyz", line 12, in calcMarks
avg = sum(list[0:len(list)])
TypeError: unsupported operand type(s) for +: 'int' and 'str'
>>> 

Here is my code so far:

def calcMarks():
    #input = Jack,10,10,9,10,10
    userInput = input('Enter marks:')
    list = userInput.split(',')
    name = list.pop(0)
    #print(type(list))
    #print(type(name))
    avg = sum(list)/(len(list)-1)
    print(name + ' ' + avg)

Answer 1

avg is a number. In order to be concatenated with other strings, it needs to be turned into a string first with str()

Also, you are summing strings, which need to be turned into numbers before being summed.

def calcMarks():
    #input = Jack,10,10,9,10,10
    userInput = input('Enter marks:')
    l = userInput.split(',')
    name = l.pop(0)
    l = [int(x) for x in l]
    avg = sum(l)/len(l)
    print(name + ' ' + str(avg))

Answer 2

The problem with your approach is that when reading from input you'll always get a string, so you'll have to cast to integer the marks to compute the mean. Here's how I would do this:

def calcMarks():
    # unpack the input into user and marks
    # having split the string by ','
    user, *marks = input('Enter marks:').split(',')
    # take the average of the marks cast to int 
    avg_mark = sum(map(int,marks))/(len(marks))
    # you can use f-strings to print the output
    print(f'{user} has an average of {avg_mark}')
    # print('{} has an average of {}'.format(user, avg_mark)) # for python 3.5<

---

calcMarks()

Enter marks:Jack,10,10,9,10,10
Jack has an average of 9.8

Answer 3

def calcMarks(): #input = Jack,10,10,9,10,10 userInput = input('Enter marks:') l = userInput.split(',')[1:] #print(type(list)) #print(type(name)) return sum(map(int, l))/(len(l))

Answer 4

String concetanation only works when variable needs to be concatenate are having same data type .

print(name + ' ' + str(avg))

Answer 5

If you wish to have the output of a function that returns an int or float value, you can add , instead of + in the print1 :

def calcMarks():
    #input = Jack,10,10,9,10,10
    userInput = input('Enter marks:')
    inputs = userInput.split(',')
    name = inputs.pop(0)
    input_list = [int(i) for i in inputs]
    #print(type(list))
    #print(type(name))
    avg = sum(input_list)/(len(input_list))
    print(name + ' ',avg)
calcMarks()

Output:

Enter marks:Jack,10,10,9,10,10
Jack  9.8

Answer 6

You could take the username and the marks in two variables, one a simple string and other a string list. Then You could proceed for the average as you already separated the name from the numbers. If I'm not wrong, then this should do your work well.

def calcMarks():
    # input Jack, <marks>...
    name, marks = input("Enter Marks"), map(int, input().split(", "))
    average = sum(marks) / len(marks)
    print(name + ' ' + str(average))