Python

Consider the following code:

funs = [lambda: i for i in range(3)]
print([f() for f in funs])

The result it [2,2,2].

funs = [lambda i=i:i for i in range(3)]
print([f() for f in funs])

or

funs = (lambda: i for i in range(3))
print([f() for f in funs])

The result is [1,2,3].

def f(n, lst=[]):
    lst.append(n)
    return lst
print(f(1), f(2))

The result is [1,2], [1,2].

def f(n, lst=[]):
    lst.append(n)
    return lst*1 # or lst[:], list(lst), lst.copy()
print(f(1), f(2))

The result is [1], [1,2].

For the shallow copy of a list, changing the top-level element does not change the original list. Only when you change the nested element, the original list will be changed too.