assign a value to a dict change all the values

[Windspar]

List are reference variables. They are always pass as reference.
When you assign one list to all variables.
It all point to the same list.

Examples

import numpy as np
td =[np.Inf, 2, 3]
a = {}

for k in range(10):
    a[k] = td # point to one list

a[0][0] = 1
td[1] = 10
for i in a.items():
    print(i)

b = {}
for k in range(10):
    b[k] = td[:] # shallow copy

b[0][0] = 2
td[1] = 0
print()
for i in b.items():
    print(i)

a = [1, 2, 3]
b = a
c = a[:] # shallow copy

print(a)
print(b)
print(c)
print()

a[1] = 6
b[0] = 5
c[2] = 7

print(a)
print(b)
print(c)