Since variables' values aren't changed inside a function, I first ran a tester for lists. It turns out they do get appended with the new values provided in the function. Here's what I tried
def test():
testlist.append(6)
testlist=[3,4]
print(testlist)
test()
print(testlist)
output:-
[3, 4]
[3, 4, 6]
But when I tried this in my actual project it didn't work. Here's part of the code:-
student_name=[]
roll_number=[]
def student_info()
sn=input("Student Name : ")
student_name.append(sn)
rn=input("Roll no. : ")
roll_number.append(rn)
the student_info() runs as many times as there are students, which is also a variable.
Each time, the list appends a value for each student. All these values will later be extracted whenever needed using the index number. But when I try to call a list value it's always the first value of the list that comes. So the list is not being appended?
def print_card():
for p in range(0,no_of_classes,1):
for l in range(0,class_strength,1):
print("Student Name:",student_name[l],x*50,"Roll No:",roll_number[l])
(please ignore the unnecessarily complex formatting part)
#This is the main part of the code.
for j in range (no_of_classes):
class_=input("Class name")
print("Class strength of ",class_)
class_strength=int(input())
for i in range (class_strength):
student_info()
print_card()
Here's the minimum reproducible program
student_name=[]
roll_number=[]
def student_info():
sn=input("Student Name : ")
student_name.append(sn)
rn=input("Roll no. : ")
roll_number.append(rn)
def print_card():
for p in range(0,no_of_classes,1):
for l in range(0,class_strength,1):
x=' '
print('\n')
print("Student Name:",student_name[l],x*50,"Roll No:",roll_number[l])
no_of_classes=2
class_strength=1
for j in range (0,no_of_classes):
for i in range (0,class_strength):
student_info()
print_card()
The card gets created for the first class but for the next class, the same output comes. Why is this happening?
Expected output vs Actual output
(say for 2 students)
kode skool
Student Name: 1 Roll No: 1
Class: 1 Section: 1
Address 1
1
City: 1 Pin Code: 1
Guardian's Phone Number 1
kode skool
Student Name: 2 Roll No: 2
Class: 2 Section: 2
Address 2
2
City: 2 Pin Code: 2
Guardian's Phone Number 2
-------------------------------------------------------------------
kode skool
Student Name: 1 Roll No: 1
Class: 1 Section: 1
Address 1
1
City: 1 Pin Code: 1
Guardian's Phone Number 1
kode skool
Student Name: 1 Roll No: 1
Class: 1 Section: 1
Address 1
1
City: 1 Pin Code: 1
Guardian's Phone Number 1
CodePudding user response：
All your problem is you keep all students on one flat list
students = [name1, name2, name3, ...]
so later it makes problem to get correctly data for second class.
You use indexes [0], [1], etc. to get students from second class but it would need
[class_1_strength 0], [class_1_strength 1], etc.
And to get students from third class you would need
[class_1_strength class_2_strength 0], [class_1_strength class_2_strength 1], etc.
so it makes big problem.
It would be much simpler if you will keep every class as sublist
school = [
[name1, name2, name3, ...], # class 1
[name1, name2, name3, ...], # class 2
# etc.
]
or as dictionary:
school = {
'class_1_name': [name1, name2, name3, ...], # class 1
'class_2_name': [name1, name2, name3, ...], # class 2
# etc.
}
Frankly, it would be good to keep all values together:
school = [
[ (name1, roll_number, ...), (name2, roll_number, ...), ...], # class 1
[ (name1, roll_number, ...), (name2, roll_number, ...), ...], # class 2
# etc.
]
Minimal working example.
I use random, string only to create some data for test - so I don't have to use input().
I use random.seed(0) to get always the same data - so I can compare them with previous execution.
import random
import string
random.seed(0)
def generate_random_name(lenght=5):
return "".join(random.choices(string.ascii_uppercase, k=lenght))
def get_student_info():
#student_name = input("Student Name : ")
#roll_number = input("Roll no. : ")
student_name = generate_random_name()
roll_number = 1
return student_name, roll_number
def print_card():
for class_number, class_students in enumerate(school, 1):
print('--- class:', class_number, '---\n')
for item in class_students:
student_name, roll_number, class_number = item
print(f"Student Name: {student_name:}")
print(f"Roll No: {roll_number}")
print(f"Class: {class_number}")
print()
# --- main ---
school = []
no_of_classes = 2
class_strength = 3
for class_number in range(1, no_of_classes 1):
class_students = [] # list for all students in one clas
for student_number in range(1, class_strength 1):
student_name, roll_number = get_student_info()
# all information about one student
item = [student_name, student_number, class_number]
class_students.append(item)
school.append(class_students)
print_card()
Result:
--- class: 1 ---
Student Name: VTKGN
Roll No: 1
Class: 1
Student Name: KUHMP
Roll No: 2
Class: 1
Student Name: XNHTQ
Roll No: 3
Class: 1
--- class: 2 ---
Student Name: GXZVX
Roll No: 1
Class: 2
Student Name: ISXRM
Roll No: 2
Class: 2
Student Name: CLPXZ
Roll No: 3
Class: 2