python 函数式编程尾递归优化 day16

#非函数式
a = 1
def incr_test1():
    global a#一旦更改全局变量后后面再调用a就容易乱
    a += 1
    return a
incr_test1()
print(a)

def bar():
    print(‘from bar‘)
def foo():
    print(‘from foo‘)
    return bar
n = foo()
n()

def hanle():
    print(‘form handle‘)
    return hanle
h = hanle()
h()()

#函数bar在foo为非尾调用
def bar(n):
    return n
def foo(x):
    y = bar(x)
    return y

#函数bar在foo内卫非尾调用
def bar(n):
    return n
def foo():
    return bar(x)+1

#非尾递归
def cal(seq):
    if len(seq) == 1:
        return seq[0]
    head,*tail = seq
    return head+cal(tail)
print(cal(range(100)))

#尾递归
def cal(l):
    print(l)
    if len(l) == 1:
        return l[0]
    first,second,*args = 1
    l[0]=first+second
    l.pop(1)
    return cal(l)
x=cal([i for i in range(10)])
print(x)