除庄周梦蝶外，庄子还讲过哪些梦你知道吗？新故事引出新版本——

def fib(n):
    match n:
        case 1|2:
            return 1
        case other:
            return fib(n-1)+fib(n-2)
for i in range(1,11):
    print(fib(i))
1
1
2
3
5
8
13
21
34
55

def fib(n):
    match n:
        case 1|2:
            return 1
        case anything:
            return fib(n-1)+fib(n-2)
fib(5)
5
fib(10)
55

i = 5
match i:
    case 1: print(1)
    case 2: print(2)
    case i: print(i**2)
25
match i:
    case 1: print(1)
    case 2: print(2)
    case n: print(i**2)
25
match i:
    case 1: print(1)
    case 2: print(2)
    case n: print(n**2)
25
match i:
    case 1: print(1)
    case 2: print(2)
    case i: print(n**2)
25
match i:
    case 1: print(1)
    case 2: print(2)
    case a: print(i**2)
25
match i:
    case 1: print(1)
    case 2: print(2)
    case i: print(a**2)
25
a
5
b
Traceback (most recent call last):
  File "<pyshell#15>", line 1, in <module>
    b
NameError: name 'b' is not defined
match i:
    case 1: print(1)
    case 2: print(2)
    case b: print(i**2)
25
b
5

help('if')
The "if" statement
******************
The "if" statement is used for conditional execution:
   if_stmt ::= "if" assignment_expression ":" suite
               ("elif" assignment_expression ":" suite)*
               ["else" ":" suite]
It selects exactly one of the suites by evaluating the expressions one
by one until one is found to be true (see section Boolean operations
for the definition of true and false); then that suite is executed
(and no other part of the "if" statement is executed or evaluated).
If all expressions are false, the suite of the "else" clause, if
present, is executed.
Related help topics: TRUTHVALUE
help('return')
The "return" statement
**********************
   return_stmt ::= "return" [expression_list]
"return" may only occur syntactically nested in a function definition,
not within a nested class definition.
If an expression list is present, it is evaluated, else "None" is
substituted.
"return" leaves the current function call with the expression list (or
"None") as return value.
When "return" passes control out of a "try" statement with a "finally"
clause, that "finally" clause is executed before really leaving the
function.
In a generator function, the "return" statement indicates that the
generator is done and will cause "StopIteration" to be raised. The
returned value (if any) is used as an argument to construct
"StopIteration" and becomes the "StopIteration.value" attribute.
In an asynchronous generator function, an empty "return" statement
indicates that the asynchronous generator is done and will cause
"StopAsyncIteration" to be raised.  A non-empty "return" statement is
a syntax error in an asynchronous generator function.
Related help topics: FUNCTIONS
help('match')
No Python documentation found for 'match'.
Use help() to get the interactive help utility.
Use help(str) for help on the str class.
help('case')
No Python documentation found for 'case'.
Use help() to get the interactive help utility.
Use help(str) for help on the str class.