#參數(shù)為函數(shù)
def bar():
    print("in the bar..")
def foo(func):
    func()
    print("in the foo..")

foo(bar)

#返回值為函數(shù)
def bar():
    print("in the bar..")
def foo(func):
    print("in the foo..")
    return bar
res=foo(bar)
res()

num=[1,2,3,4,5]
def square(x):
    return x**2
#map函數(shù)模擬
def map_test(func,iter):
    num_1=[]
    for i in iter:
        ret=func(i)
        # print(ret)
        num_1.append(ret)
    return num_1.__iter__() #將列表轉(zhuǎn)為迭代器對(duì)象

#map_test函數(shù)
print(list(map_test(square,num)))
#map函數(shù)
print(list(map(square,num)))

#當(dāng)然map函數(shù)的參數(shù)1也可以是匿名函數(shù)、參數(shù)2也可以是字符串
print(list(map_test(lambda x:x.upper(),"amanda")))
print(list(map(lambda x:x.upper(),"amanda")))

names=["Alex","amanda","xiaowu"]
#filter函數(shù)機(jī)制
def filter_test(func,iter):
    names_1=[]
    for i in iter:
        if func(i): #傳入的func函數(shù)其結(jié)果必須為bool值，才有意義
            names_1.append(i)
    return names_1
#filter_test函數(shù)
print(filter_test(lambda x:x.islower(),names))
#filter函數(shù)
print(list(filter(lambda x:x.islower(),names)))

#reduce函數(shù)不是內(nèi)置函數(shù)，而是在模塊functools中的函數(shù)，故需要導(dǎo)入
from functools import reduce

nums=[1,2,3,4,5,6]
#reduce函數(shù)的機(jī)制
def reduce_test(func,array,ini=None): #ini作為基數(shù)
    if ini == None:
        ret =array.pop(0)
    else:
        ret=ini
    for i in array:
        ret=func(ret,i)
    return ret
#reduce_test函數(shù)，疊乘
print(reduce_test(lambda x,y:x*y,nums,100))
#reduce函數(shù)，疊乘
print(reduce(lambda x,y:x*y,nums,100))