User IDs not being updated in binary file (python)

Question

**Aim:** Creating a binary file with Student ID, name and User ID. Taking a student ID as input from and updating the user ID.

So I created the file:

#creating the file

import pickle

data=[[12, "Hook", 97], [45, "Lola", 65], [34, "Maya", 99], [79, "Lumberjill", 100]]
with open("sheets.dat","wb") as m:
for i in data:
pickle.dump(i,m)

Reading the contents before update:

#reading file contents

m=open("sheets.dat", "rb")

try:
while 1:
j=pickle.load(m)
print(j)

except EOFError:
m.close()

**Output:**

[12, 'Hook', 97]
[45, 'Lola', 65]
[34, 'Maya', 99]
[79, 'Lumberjill', 100]

Updating the User ID:

#update on marks

m=open("sheets.dat", "rb+")
roll=int(input("Enter SID:"))
try:
while 1:
pos=m.tell()
j=pickle.load(m)
if j[0]==roll:
marks=int(input("Enter updated UID:"))
j[2]==marks
m.seek(pos)
pickle.dump(j,m)

except EOFError:
m.close()

However, after the update (Tried to change Lumberjill's UID to 54):

[12, 'Hook', 97]
[45, 'Lola', 65]
[34, 'Maya', 99]
[79, 'Lumberjill', 100]

Nothing's really changed.

Now, where did I mess up?

Answer 1

May be indentantion in line : except EOFError update