test_args_in_params.py

# WHY parameters that are mutable in params


def foo_str(l='A', a=None):
    print('BEFORE')
    print(l)
    print("AFTER")
    l + a
    print(l)


def foo_list(l=[], a=None):
    print('BEFORE')
    print(l)
    print("AFTER")
    l.append(a)
    print(l)


CONST_LIST = []


def foo_list_const(l=CONST_LIST, a=None):
    print('BEFORE')
    print(l)
    print("AFTER")
    l.append(a)
    print(l)


def foo_list_good(l=None, a=None):
    if l is None:
        l = []

    print('BEFORE')
    print(l)
    print("AFTER")
    l.append(a)
    print(l)


foo_str(a='B')
foo_str(a='a')

print("TEST WITH [] in PARAMS")

print("FIRST \n")
foo_list(a='haha')
print("Second \n")
foo_list(a='haha2')

print("TEST WITH [] as CONST")

print("FIRST \n")
foo_list_const(a='haha')
print("Second \n")
foo_list_const(a='haha2')

print("TEST WITH NONE THEN init inside")

print("FIRST \n")
foo_list_good(a='haha')
print("Second \n")
foo_list_good(a='haha2')



# >> OUTPUT



    # BEFORE
    # A
    # AFTER
    # A
    # BEFORE
    # A
    # AFTER
    # A
    # TEST WITH [] in PARAMS
    # FIRST 

    # BEFORE
    # []
    # AFTER
    # ['haha']
    # Second 

    # BEFORE
    # ['haha']
    # AFTER
    # ['haha', 'haha2']
    # TEST WITH [] as CONST
    # FIRST 

    # BEFORE
    # []
    # AFTER
    # ['haha']
    # Second 

    # BEFORE
    # ['haha']
    # AFTER
    # ['haha', 'haha2']
    # TEST WITH NONE THEN init inside
    # FIRST 

    # BEFORE
    # []
    # AFTER
    # ['haha']
    # Second 

    # BEFORE
    # []
    # AFTER
    # ['haha2']