如何在python中打印字典键和值

Question

I have to make a program which asks the user to enter a student name, and their grade, for every student. And put them as [keys] and [values] in a dictionary. And when the user enters 'q' the program quits and then prints the students and their grades such as this:

Student Grade
Student1 A
Student2 B
Student3 C

My code looks like this:

student_grades = {}

while True:

    ## Get the Name [key in dictionary] of the student
    name = raw_input("Please give me the name of the student (press q to quit): \n")

    if name == 'q':
        print "Okay, printing grades! \n"
        for x in student_grades:
            print student_grades.keys() + student_grades.values()
        break

    # Chcek if name isn't valid
    elif name.isdigit():
        print "Sorry, {} isn't valid".format(name)
        name = raw_input("Please give me the name of the student (press q to quit): \n")

    ## Get the grade [value in dictionary] of the student
    grade = raw_input("Please give me their grade: (e.g 'A', 'B', 'C', 'D', 'F') \n")

    # Check if grade isn't valid
    if not grade in ['A', 'B', 'C', 'D', 'F']:
        print "Sorry, {} isn't valid".format(grade)
        grade = raw_input("Please give me their grade: (e.g 'A', 'B', 'C', 'D', 'F') \n")
        # Assign Name to Grade
        student_grades[name] = grade

When I enter 'q' the program should print the keys and values which are the student name and their grade, but it prints nothing

Answer 1

You can access the keys and values of a dictionary like this:

for k, v in mydict.iteritems():
    print(k, v)

In Python 3 this is changed/bettered to:

for k, v in mydict.items():
    print(k, v)