Expected type 'str', Tuple[str] was returned in python3.8-CodePudding

Expected type str, Tuple[str] was returned in python3.8

CA2 = "2CA",
CA3 = "3CA",
CA4 = "4CA",
LTE = "LTE"
def temp() -> str:
    ca_list = [1, 2, 3]
    if len(ca_list) == 1:
        result = LTE
    elif len(ca_list) == 2:
        result = CA4
    elif len(ca_list) == 3:
        result = CA2
    else:
        result = CA3
    return result
temp()

output: ('2CA',)

CodePudding user response：

The comma after each automatically converts the string such as "2CA" to a tuple like ('2CA',) so therefore your output is a tuple containing it.

if you want a string output just remove the commas

see here: Why does adding a trailing comma after a variable name make it a tuple?

CodePudding user response：

Expect for LTE all are tuples i.e CA2, CA3, CA4. In python () doesn't make it a tuple but ,(comma) does.

a = (1) # a is 1 not tuple of size 1
b = 1, # or (1, ) now b is tuple of size 1.
c = 1, 2, 3 # c is (1, 2, 3)