[Python] Function traps

First, the local variable is static detection

The variable names that are assigned in the function are default to local variables (following the LEGB rule), they exist in the scope of the function, exist only when the function runs, the function ends, and the variables disappear.

Second, the default variable object

The default parameters of a mutable type save their state between function calls

Three, no Return statement function, returns none

1 defSaver (x=[]):2X.append (1)3     Print(x)4     5 Print(Saver ([2]))6 Print(Saver ())7 Print(Saver ())8 Print(Saver ())9 Ten #Output One[2, 1] A None -[1] - None the[1, 1] - None -[1, 1, 1] -None

[Python] Function traps