函數(shù)作用域
name = 'alex'

def foo():
    name = 'linhaifeng'
    def bar():
        name = 'wupeiqi'
        print(name)
    return bar
a = foo()
a()

def test1():
    print('in the test1')
def test():
    print('in the test')
    return test1
print(test)

res = test()
print(res)

name = 'alex'
def foo():
    name = 'lhf'
    def bar():
        name = 'wupeiqi'
        def tt():
            print(name)
        return tt
    return bar

bar = foo()
tt = bar()
tt()
foo()()()

匿名函數(shù)

lambda x:x+1

def calc(x):
    return x + 1


a = calc(10)
print(a)

x = lambda x:x+1

print(x(10))


name = 'alex'

def change_name(name):
    return '%s _sb' %name

a = change_name(name)
print(a)

s = lambda name:name+'_sb'

print(s(name))

v = lambda x, y, z: x + y + z
print(v(1, 2, 3))

v = lambda x, y, z: (x + 1, y + 1, z + 1)
print(v(1, 2, 3))

函數(shù)式編程
編程的方法論

面向過(guò)程
1、搜索目標(biāo)
2、表白
3、戀愛(ài)
4、見(jiàn)家長(zhǎng)
5、結(jié)婚

函數(shù)式 = 編程語(yǔ)言定義的函數(shù) + 數(shù)學(xué)意義的函數(shù)
1、數(shù)學(xué)模型  y  = 2 * x + 1
2、難懂
3、特性：不可變，不用變量保存狀態(tài)，不修改變量


高階函數(shù)
1、函數(shù)作為參數(shù)傳給函數(shù)
def foo(n):
    print(n)

def bar(x):
    print(x)

foo(bar(1))

2、返回值中包含函數(shù)
def bar():
    print('from bar')

def foo():
    print('from foo')
    return bar

ar = foo()
ar()

def handle():
    print('from handle')
    return handle()

h = handle()
h()

def test1():
    print('test1')
def test2():
    print('test2')
    return test1()

尾調(diào)用優(yōu)化  最后一步進(jìn)入遞歸
尾調(diào)用
def bar(n):
    return n
def foo(x):
    return bar(x)

不是尾調(diào)用
def bar(n):
    return n
def foo(x):
    return bar(x) + 1

面向?qū)ο?

map 函數(shù)

num_1 = [1, 2, 23, 78, 22]

add_one = lambda x: x + 1
ress_one = lambda x: x - 1
ff_w = lambda x: x ** 2


def map_test(func, array):
    res = []
    for i in array:
        res.append(func(i))
    return res


print(map_test(add_one, num_1))

map(函數(shù),可迭代對(duì)象)
v1 = map(lambda x: x + 1, num_1)

yy = []

for i in v1:
    yy.append(i)
    print(i)
print(yy)

print(v1)

filter() 函數(shù)
movie = ['sb_alex', 'wupeisbqi', 'yuanhao_sb', 'sb', 'lihaifeng']


def filter_test(func, array):
    goout = []
    for i in movie:
        if not func(i):
            goout.append(i)
    return goout


print(filter_test(lambda x: x.endswith('sb'), movie))

print(list(filter(lambda x: not x.endswith('sb'), movie)))

reduce()

numl = [1, 2, 3, 4, 5]


def reduce_test(func, numl, init=None):
    if init is None:
        res = numl.pop(0)
    else:
        res = init
    for num in numl:
        res = func(num, res)
    return res


print(reduce_test(lambda x, y: x * y, numl, 100))

from functools import reduce

r = reduce(lambda x, y: x * y, numl)

print(r)

總結(jié)

map()  序列中每個(gè)元素得到的結(jié)果是一個(gè) '列表'，該 '列表'元素個(gè)數(shù)及位置與原來(lái)一樣


filter() 遍歷序列中的每一個(gè)元素，判斷每個(gè)元素得到布爾值，如果是True 則留下來(lái)。

people = [
    {
        'name': 'alex1',
        'age': 1000,
    },
    {
        'name': 'alex2',
        'age': 10000,
    },
    {
        'name': 'alex3',
        'age': 9000,
    },
    {
        'name': 'alex4',
        'age': 18,
    }
]

a = list(filter(lambda x: x['age'] <= 18, people))
print(a)

reduce() 處理一個(gè)序列，然后對(duì)序列進(jìn)行合并操作

內(nèi)置函數(shù)

絕對(duì)值
print(abs(-222))

序列中的每一個(gè)元素布爾值  一個(gè)為假就是假  如果可迭代函數(shù)為空  則為True
print(all([1, 2, 3, 4, 55, '222', '']))  False
print(all([])) True

any()  有一個(gè)真即為真
print(any([1, 2, 3, 4, 55, '222', ''])) True

bin() 10進(jìn)制轉(zhuǎn)2進(jìn)制
print(bin(20))

判斷bool 假的值 0 None ''
print(bool(''))

字符串轉(zhuǎn)成字節(jié)  用什么編碼用什么解碼
v = '000'

print(bytes(v, encoding='utf-8'))

print(bytes(v, encoding='utf-8').decode('utf-8'))

print(bytes(v, encoding='gbk'))

print(bytes(v, encoding='ascii'))

chr()  對(duì)應(yīng)ascii 碼存儲(chǔ)的
print(chr(97))

打印某一個(gè)對(duì)象都有什么方法
print(dir(all))

取余數(shù)
print(divmod(10, 3))

提取字符串中的數(shù)據(jù)結(jié)構(gòu)  字符串中的數(shù)學(xué)運(yùn)算
dic = {'name': 'alex'}
dic_str = str(dic)
print(eval(dic_str))

express = '1+2*(3*3)'
print(eval(express))

hash()  可hash的數(shù)據(jù)類型即不可變的數(shù)據(jù)類型，不可hash數(shù)據(jù)類型是可變數(shù)據(jù)類型
print(hash('12sdasdasdasdasdasdasdasdasd3'))

help()

isinstance() 判斷數(shù)據(jù)類型
print(isinstance(1, int))

查看全局變量  查看局部變量
name = 'sd'
print(globals())
print(locals())

max() min()
name = [1, 23, 33, 2]

zip()  兩個(gè) 序列  元祖  列表 字符串
print(list(zip(('a', 'b', 'c'), (1, 2, 3))))
print(list(zip(('a', 'b', 'c'), (1, 2, 3, 4))))
print(list(zip(('a', 'b', 'c', 'd'), (1, 2, 3))))

p = {'name': 'alex', 'age': 18}

print(list(zip(p.keys(), p.values())))

print(list(zip(['a', 'b'], '123456')))

age_dic = {'age1': 18, 'age2': 20, 'age3': 67}

print(max(age_dic.values()))
print(min(age_dic.values()))

默認(rèn)比較字典的key
print(max(age_dic))

print(list(max(zip(age_dic.values(),age_dic.keys()))))


ll = ['a10', 'b12', 'c10', 100]  #不同類型不能進(jìn)行比較
ll = ['a10', 'b12', 'c10']
print('----->', list(max(ll)))

min()  max() 高級(jí)用法
1、簡(jiǎn)單數(shù)據(jù)直接比較
2、復(fù)雜比較
people = [
    {
        'name': 'alex1',
        'age': 1000,
    },
    {
        'name': 'alex2',
        'age': 10000,
    },
    {
        'name': 'alex3',
        'age': 9000,
    },
    {
        'name': 'alex4',
        'age': 18,
    }
]

print(max(people, key=lambda dic: dic['age']))

十進(jìn)制轉(zhuǎn)8進(jìn)制
print(oct(10))

顯示對(duì)應(yīng)ascii 碼表對(duì)應(yīng)的字符
print(ord('a'))

3**3%2
print(pow(3, 3, 2))

reversed() 翻轉(zhuǎn)
lii = [1, 23, 4]
print(list(reversed(lii)))

四舍五入
print(round(3.5))

l = 'hello'
print(l[3:5])

s1 = slice(3,5)  還可設(shè)置步長(zhǎng)  s1 = slice(1,4,2)
print(l[s1])

排序
l = [3, 2, 1, 5, 6, 18, 'a']   #本質(zhì)就是比較大小，不同類型不能排序
print(sorted(l))
people = [
    {
        'name': 'alex1',
        'age': 1000,
    },
    {
        'name': 'alex2',
        'age': 10000,
    },
    {
        'name': 'alex3',
        'age': 9000,
    },
    {
        'name': 'alex4',
        'age': 18,
    }
]
print(sorted(people, key=lambda dic: dic['age']))

dic = {
    'aoop': 100,
    'ooi': 300,
    'iuy': 500
}

print(sorted(dic, key=lambda key: dic[key]))

print(sorted(dic, key=lambda key: dic[key]))

print(sorted(list(zip(dic.values(),dic.keys()))))

數(shù)據(jù)類型
sss = 'sss'
print(type(sss))

求和
print(sum(range(5)))

類型判斷  type()

vars()  如果沒(méi)有參數(shù)和locals一樣   如果有參數(shù)

def test():
    msg = 'sdada0'
    print(locals())

print(vars(int))

test()


import 不能導(dǎo)入字符串
__import__ 導(dǎo)入字符串