《零基础入门学习Python》(20)--函数:内嵌函数和闭包

前言

之前我们讲了函数的一些相关知识,了解了什么是全局变量什么是局部变量,接下来我们看看怎么将局部变量变为全局变量。还要将将内嵌函数的相关概念

知识点

  • global关键字 
    使用global关键字,可以修改全局变量:
>>> count = 5
>>> def Myfun():
        count = 10
        print(10)

>>> Myfun()
10
>>> print(count)
5
--------------------------------
>>> def Myfun():
        global count
        count = 10
        print(10)


>>> Myfun()
10
>>> print(count)
10
>>> 
--------------------- 
  • 内部函数 
    函数内部新创建另一个函数
>>> def fun1():
        print('fun1()正在被调用...')
        def fun2():
            print('fun2()正在被调用...')
        fun2()


>>> fun1()
fun1()正在被调用...
fun2()正在被调用...
  • 闭包(Closure) 
  • 如果在一个内部函数里,对外部作用域(但不是在全局作用域的)变量进行引用,那么内部函数就会认为是闭包
>>> def FunX(x):
	def FunY(y):
		return x*y
	return FunY

>>> i =FunX(8)
>>> type(i)
<class 'function'>
>>> i(5)
40
>>> FunX(8)()#错误举例
Traceback (most recent call last):
  File "<pyshell#17>", line 1, in <module>
    FunX(8)()
TypeError: FunY() missing 1 required positional argument: 'y'
>>> FunX(8)(5)
40
>>> FunY(5)
Traceback (most recent call last):
  File "<pyshell#19>", line 1, in <module>
    FunY(5)
NameError: name 'FunY' is not defined
>>> 
  • nonlocal关键字 
    用于声明局部变量
>>> def Fun1():
        x = 5
        def Fun2():
            x *= x
            return x
        return Fun2()

>>> Fun1()
Traceback (most recent call last):
  File "<pyshell#51>", line 1, in <module>
    Fun1()
  File "<pyshell#50>", line 6, in Fun1
    return Fun2()
  File "<pyshell#50>", line 4, in Fun2
    x *= x
UnboundLocalError: local variable 'x' referenced before assignment

原因:其存放在栈空间,如果修改,则会在局部函数作用域中屏蔽外部变量,就会出现引用了没有定义的变量值的错误。

解决办法:在python3之前没有直接的解决办法,只能间接通过的容器来解决,因为容器类型不存放在栈里边,所以变量不会被屏蔽。

第一种解决方法:(因为队列没有存放在栈中)

>>> def Fun1():
        x = [5]
        def Fun2():
            x[0] *= x[0]
            return x[0]
        return Fun2()

>>> Fun1()
25

第二种解决方法:python3之后可以使用nonlocal关键字来解决了,在使用函数外部变量的时候在使用前先用关键字nonlocal声明一下:

>>> def Fun1():
        x = 5
        def Fun2():
            nonlocal x
            x *= x
            return x
        return Fun2()

>>> Fun1()
25

课后作业

测试题

  • 如果希望在函数中修改全局变量的值,应该使用什么关键字?
global 关键字

例如:
>>> count = 5
>>> def MyFun():
                global count
                count = 10
                print(count)

>>> MyFun()
10
>>> count
10
  • 在嵌套的函数中,如果希望在内部函数修改外部函数的变量,应该使用什么关键字?
#nolocal关键字

#例如:
>>> def Fun1():
                x = 5
                def Fun2():
                        nonlocal x
                        x *= x
                        return x
                return Fun2()

>>> Fun1()
25
  • Python的函数可以嵌套,但要注意访问的作用域问题,请问以下代码存在什么问题呢?
def outside():
    print('I am outside!')
    def inside():
        print('I am inside!')

inside()

使用嵌套函数要注意一点就是作用域问题,inside()函数是内嵌在outside()函数中的,所以除了outside()可以调用,在外边或者别的函数体里都无法对其进行调用的。

正确的调用应该是(注意空格的位置):

def outside():
    print('I am outside!')
    def inside():
        print('I am inside!')

    inside()
outside()
  • 请问为什么代码A没有报错,但代码B却报错了?应该如何修改?
代码A:
>>> def outside():
        var = 5
        def inside():
            var = 3
            print(var)
        inside()

>>> outside()
3

代码B
>>> def outside():
    var = 5
    def inside():
        print(var)
        var = 3
    inside()

>>> outside()
Traceback (most recent call last):
  File "<pyshell#81>", line 1, in <module>
    outside()
  File "<pyshell#80>", line 6, in outside
    inside()
  File "<pyshell#80>", line 4, in inside
    print(var)
UnboundLocalError: local variable 'var' referenced before assignment

报错原因分析:
说的是变量var没有被定义就拿来使用,肯定错啦!

这里outside()函数里有一个var变量,但要注意的是,内嵌函数inside()也有一个同名的变量,Python为了保护变量的作用域,故将outside()的var变量屏蔽起来,因此此时是无法访问到外层的var变量的。

应该修改为:
>>> def outside():
        var = 5
        def inside():
            nonlocal var
            print(var)
            var = 3
        inside()

>>> outside()
5
  • 请问如何访问funIn()呢?
>>> def funOut():
        def funIn():
            print('宾果!你成功访问到我啦!')
        return funIn()

-------------直接调用----------------
>>> funOut()
宾果!你成功访问到我啦!


>>> def funOut():
        def funIn():
            print('宾果!你成功访问到我啦!')
        return funIn

>>> funOut
<function funOut at 0x000000A7EC476F28>
>>> funOut()
<function funOut.<locals>.funIn at 0x000000A7EC476E18>

>>> funOut()()
宾果!你成功访问到我啦!
  • 以下是“闭包”的一个例子,请你目测下回打印什么内容?
>>> def funX():
        x = 5
        def funY():
            nonlocal x
            x += 1
            return x
        return funY

>>> funX()()
6
>>> funX()()
6
>>> funX()()
6


>>> a = funX()
>>> print(a())
6
>>> print(a())
7
>>> print(a())
8

#有些鱼油可能会比较疑惑,这怎么跟全局变量一样了?局部变量x不是应该在每次调用的时候都重新初始化了吗?

#其实大家仔细看就明白了,当a = funX() 时,只要a变量没有被重新赋值,funX()就没有被释放,也就是说局部变量x就没有被重新初始化。

所以当全局变量不适用时,可考虑用闭包更稳定和安全,你还可以参考 

游戏中的角色移动闭包在实际开发中的作用

动动手

请用已学过的知识编写程序,统计下边这个长字符串各个字符出现的次数,并找到小甲鱼送给大家的一句话。

string1 ='''%%$@_$^__#)^)&!_+]!*@&^}@[@%]()%+$&[(_@%+%$*^@$^!+]!&_#)_*}{}}!}_]$[%}@[{_@#_^{*
@##&{#&{&)*%(]{{([*}@[@&]+!!*{)!}{%+{))])[!^})+)$]#{*+^((@^@}$[**$&^{$!@#$%)!@(&
+^!{%_$&@^!}$_${)$_#)!({@!)(^}!*^&!$%_&&}&_#&@{)]{+)%*{&*%*&@%$+]!*__(#!*){%&@++
!_)^$&&%#+)}!@!)&^}**#!_$([$!$}#*^}$+&#[{*{}{((#$]{[$[$$()_#}!@}^@_&%^*!){*^^_$^
]@}#%[%!^[^_})+@&}{@*!(@$%$^)}[_!}(*}#}#___}!](@_{{(*#%!%%+*)^+#%}$+_]#}%!**#!^_
省略大部分。
'''

list1 = []
for each in string1:
    if each not in list1:
        if each == '\\n':
            print('\\n',string1.count(each))
        else:
            print(each,string1.count(each))
        list1.append(each)

运行结果:

================= RESTART: C:\Users\ThinkPad\Desktop\test.py =================
% 26
$ 30
@ 28
_ 30
^ 27
# 24
) 26
& 25
! 33
+ 19
] 14
* 28
} 30
[ 15
( 18
{ 27

 6
省 1
略 1
大 1
部 1
分 1
。 1
  • 请用已学过的知识编写程序,找出小甲鱼藏在下边这个长字符串中的密码,密码的埋藏点符合以下规律:
1)每位密码为单个小写字母 
2)每位密码的左右两边有且均只有三个大写字母
str1 = '''ACFlCTLIQlAIVMTqHFkswqbDDHtpgcWaXSSglUYKE
lqNsYCyaQXBzrFUbkAUAWAKrDgDtAlGMBqWQhpEwquZqWZJpslUfMllCwWptqINjrOBTLuPzwvXNbLCx
oFRritKRpJgBOaGPZdkUzvYnvYmAlEsVmKRXqyQUOdCBqLYyboOYeAQNLnkuiDXCiNiksSSRpDMVQQgs
TmYThnppfKSmkpjjceGLaMOvYgsvNkGENKgGtUSzVPlLMeephDKrWGNpAxBqRiCnQIuKwDZurIRsznUp
xhstMWpHdZzqeEnttlAHiWbhbIJpwKBAGsFWthBiwBDKTFzIUamELZJFLbmqOmwBIYBJIofAUyxTLUEm
LcOXzjIHFcfUfEWccbWzhVuIZMdTVsOaNsLTpHjrvFaYTnJUrqaYnUmbobfOXXtkjKjFUEhVNlPWeaIY
uABNuEDKFWiUaqQiBHGsgEmDSKiJKLkkzFWlobXIyUlDzGcwDnEOwwWxgFpebsslmKItazIYctPROSJp
ImDHusQIkoFQSmuqwdcPNERvflfHtkGTrtbQXqZUsazoxmbVTPIuuxKvfALAaGnIuIZwczCcoIRMncBs
timFGHPJPaHMPTLjsBjIwbbzKyghaDTUStzJceaYAneywwpvdiUJifPHtXmAwZPChWsDmwonzeeQCEiB
xWsJLAtrdVEOBxEaYiSabHdUwlXlDOAKzZUwozJoBGvnFttDkXdYdjQSzzhTIPfYpWVFdiFIqSbyPZIi
VoXunBPbAJVMWluPcIfHmjPeHaTyClCvTOucEYEZXbVDiZMsfeuruDGMmQEsHutzvzVmWvCoPRguBiHh
taTeaguPmNuAxzYJLEcdoApfIFBaLUqettjTJNlHZYlJZRRoKXEvFnoUHdPjDuXuTAubGODkHAokpItw
SlEwhjrUSlfMawWlTMciWAzVcgPcqCHIaogokYAWGsvWZzBfJqzxIkCNvHDvBkOMCyeYXzVVuRJLQIOy
BMoVPgFLOagDxyPfWxTtZQNCLOrVVclPzMNYruNUyMOBKxBvinxuGMAAfndhPsROtkOJAAJQSxpmTzXm
CmEwZOhlItvETUneqvdKLghLyREjuJWRFjVVuNMiPuvvmRaEUmjCXDVuMRAvBuHUYGKPXthWISIbueRp
uvxpmqclmrXpAGFrxhJGxQwlrbkHEmcEUooCoPqGzbrCfIWmtUKmzzXvcqbhxKcAwXCNjbJDWDndKiLK
HwaFKyhXJQgHjIaTfIJrkhUpTHJZebRertDigQtDKxGerMRgHWFTrqqZlcBjAUfTZdFlZCAEZnhzgTIy
gJSsWJjFcCVoFonAfKPTOhTxjxTRtzSKLoIOScEwBCDvWFDVGpBOpijqdwvugoYsyuIOZJTcySDrzy
wBxediHOIYgasrUIDsNZcParqTGfTaBZHoSssXGtiCVvLReyoiitzMpsouqUeMHGWwDMgBaQTRkxPwNP
XsvyFVXfjgKuamMTsEsbeKDgAdVndyDleenPBcXWKGPcDsALDajkCEGufvbtyXUZnelqISbQnHphDoTH
RMIxMKclpWSvQHkzRhdAehBVaKYaXRPMpGaeRxvTRVFfewirvIDoGvYTAvKSoMFCLUNVFVKrYMeYtBrS
KgiBOjvliNOHLrmztypGhQjtpEQwzVfpVqsTUPvOCPzgqOuvLXJBQZHLmSwGTxEMgCAbogXombCiBDNX
BvGtXjrGWbWHtNCoRuqIZPhBQXZiNUhbmzOiyByAoMSBvusppiPVibIqmLXwXEVfcEAyNeUxaEZThULu
mkGmoLrpOEktwRluXvOmmfEWxZkxUNIqZKuzbaUmLKBYrXMmdOYLEzljzbSJnqRbSiAFyUNyyieKITkh
mvkKyosXKCaTsXQIKczJmxuqIEKeGGGwZyWTolQynlWngjDzFMlwhJFEmODeycbEfxgSRbIXySfwlhZZ
BUBhKyGBHRzWGRXAzarcmSDORvaOMOqYlcVIMwlHGtrLMhFWioqeKfvsJdTXmfQzavzSzCRrVzLFMaBT
DMOPFJcjzXcPvBkzacRmVKTQAvVobGRBypFHvoUdjvBhwWXVdDjvfJOocyIHbMqZGMaRaaFFnmtvTSkY
nIHbmPAtuEszMDFURBYxcOJXKMvJbfSbhiaacxhxiZBnoHTcFeqXQfjTqpcMKFpvvzkpSxlDxSlhikFZ
XSplcknpxiZfwUwGsrfpBUkevEiwndkKrVpWKufWpLTWXcyyXehOcDfnzgTAkhwOAcaiHqJWzsuAvMyD
pDJgeCdAJMwatRfcpKQGTkwxHracsYOlZeXoGthHIRfDBYzhuGEQRKFRnqSEbWDCJObWSAoSwFzVZEnI
rVBwXibUaTwnSTwRmIwkIgoGPRiOMLOTvnzEBBCfcugYZwGSsHRKCJoRsxxzRkKwnTRcRNfbMGssqmXV
IKYzyWHIsCjdzxiHEtvHaufVgcoqVkqIQertevTUTIVMYlNXCGEUzQowqsFpciURKoUwqCRogxeghOWs
cMnuAathgFvNIVqqXpmdJDJPhXQpZCyNbTYktMyTUtQEBeQBhEZzqHotmYREADhFodlcPmTMutBZyefW
sBmsnUbVnHUGAyaDirMoowBwXnzrmfHJgfpAquFoHTuvQvIJcjqiqVdntXbgwpVywbsKxqUMNxYVxBmQ
OAcxOAVPuJeOgABYEHhevhnUOgCUuTBAhJcUGsasbMInGCbHnHXWDdXijDRkUYFuOytTcMPtWklmTHTR
XFTfcFfSSqFUFbQVCKEjUOLveXtsHrIfkphXyDkRELnaTfuaZUClLqbdpWAREJHJpycYRDjElqlVeNya
kTCjDpvFrdnlXogrDZdQzAYaePDdfvHWdcaQGgrrHKBdMnMYbsikbkffVsITSUhEapmLGQYbHoiKGRcg
GPLeEvmCOAkGIuDBdnYPlzuUmLOfetGXpbTbPjjWCZiOJxlDazSbEPVpnNLDsLiwlgleiCdPezQwnNWT
ECLuRGpfJZlnZtcghLucmvlOZNwXaikbKGmoGZJIcsfNnmaHIcPXiEYDHjLKpVtNsqemAmaiTIzvLqlU
mlcvraikZozZwBoExUkELoiaAbTAkqDhrARHQyAvWvYUjthfWjZqbQNTnkgmySsORxGcxouYcyCSkjmC
fpTGOlFoXWLINurMZdQURRnZCiZqsEKeVVZdFMnaoUepdAdARtUuXTvkGzmpEVNZiYSWJAwkcSKgAWTD
mUNVxVebIiavuOAxWUBkuUkXCYtRoZhVNwCZGlaANNpBvXgSDeLURUdQnQteKAXbGlOLGYYYCzCGjzua
UmrdPYuRrUBvLFfwBGTiABTmpANdPCptqKwWXARMKrtmbggOBDgNkeHzNUCIXUIuOAavRbLTnzNNRgzL
boTJooLJIdVFbbjWNngnzPznJglCLEWqulqzSuAyvqYdivDqxEtYPKTwVheFmDidEOnLqjPHBcjoOVvt
MCDmQfwNxkOPuxiJqLQOPRAGJappmpikgmrvRAlKjFjTlaznQldBJmzSMDvCWghWOgfhfkHFZBNdbmMf
MsaQHrtJQvZuGFCrPVBNSNZBFZRdpmQNZYZXpkGjXRAXhELlxDfGhiXwgAUujQbqUCiKaRIYruNDRDlL
zInUkJBpySRZoqwQlqmoxADBjjtGjFPLTkcexYGwGYlANZQaXNgKkPXUUqlViVzxPxxtMQPqOxTcChCg
dvKNliVwzRfMmSsBFeuePnbmVqvyfdOXnZpUopEqfCMnnXpfZnNYwNKiZFPUWWmNCMibsyQEhiodVjTz
UxsicVsZNMXyvBLrdJxGGeCPEutNCzYBRamXwRlmVdqUTPnUoAWaVDshgTHZhvhVlLZsoqbyqOjJMPac
hHqiCKhgFkDUhUDSwsrEwaBrKhXINTjYmHvsTyFdRHliydbfQtRFZcsSTfcSfqyIgQuXLZnrdAwylBmW
BRbmVwdoNFcnoxMKHaYOhgihIsKitcrgEkfjIOKsDPOadFhMwVSKWeCfxxxfWjgNiGDaiYDtMhCgedOR
nTYoeVrpGsyDIsuKhffqaEqoqfWukaQlcUShYicuZAdoYVGvRchUgcmNwxQGogDvKhyAkIuqHCIXQfXp
CtkSSTXTugolUKfqSzugIOpyHhIlcTjDBTKPqcyaRhmgFdSBkYurnvnukNGVoxpZBFmwIEmehuaUcoeu
btkjJqKcAAqxgrKcoRGuqHVUHqKgEaqRCIXlaTqaUewJBEWnTnTJIDYdLeGUMDfndHPYTAGQbhxreADo
WZtdvbJVnNGRNvlAsqIPlpXSXEZGBdqVyNCCwylcXprVoGqnPXZioKnqbdrYlDhbsTVDJqRQKoPtQXzu
RnrGgCfYfeRRxiihjItxHurPwtYJoObDzlEABeIRxQocvWrJtyWchmZXJdYvTgicUircdiMKYAkNbdKu
gPpzXnTQIZxtIhvfBfjIHRaDXbYExxYBvrejpEaVHlinHlYRrhsbChnAwTKlQtHntqcqiXZwTUEdlsVy
WFdZNRfqzkhWzeKMGmkuKoSkuSZRkddsuBNFVMFLPeUkLwCCDKagNjMZwtHcVcEEKyjAYubHipuqNjaV
JukystpMZrhBgLqRVMpaIPsyAvYIsBDVqKNCMLqLwyhJhuWDdCPBgSzJTLkJvaGPirOFwfuMtkyXeKoZ
rGPRJqXyhdYNOXVSqGvbSPozAbjhpyfgGVuNUYaRQomzrTtzAMJnYnyvDnuBkbVvmYzhlhqmwgCZaGJG
GGRbaFdfnDlUfCfhpDWTkWfpUDuUksJvRFNxVYBKGoxBCdhmYZwyDPzWihcQXgByRbYxWZslVsbuTHTf
vaulICCTRkkiYuYoqFdzuxsqOBkzEJHbNXhSnHYxyeGoEklCeaUVEtjxmXyOEzcpsAhfKCTejxOxwGYh
eLtoPpPINviTCHUsgzSkycIxtvekMaoZkBIyLboyvMxxaqfviBxkSALNjiNYqGTypcZDvHonaVBZCSLp
SjRTsJmDuPwKnYwCdTprFvbXnrhARNToXpryIfEoIwSWIdfSKeOHDYwgyUvwXXpKUKQEiyZxCsTkAjME
hdxShAAUYJTkprXuFITxxJuKMiphRAyAeUFZgknMMLvUaSjiMlGmLARvTMpllxEQyfvEqkcONHVFcaTW
tqcbVrgeTLTGuJsrjZdYrrjtoLKcEfjkIhjzXgEkYhZggujFJuQlVtSqvuejtxAEqjgXrYjmwLkSRmXp
pkTfONxRyAxRYqJccLxuhabwMTWfwLTlzuVGJtVJOXxwKjFIZENpGHwRvTRitDBQBesRYATKhmWmmmbP
EXOzdBHNeghlqpjJFmzXyADNHQNEThWDyMsGsTmyFnywIPvDSIcxHbKQHgmJEcfsPzYvSYIbQjnTAgzF
UfZAbwfgCMRxtmZQQyayJFFhCSVeeUcQzSLWqhENNUpyLZaJsQsFQsPyFIjGtcmoJaFQGKTFtKUBdBBo
xECKHgYSMcBWnzRvPyihfjwyjhTTavfYqOrbrgZDSrwVYFjNsdxLJIigfMgythUoUIVSydOnfhAaesXZ
kfyDztQiBCMHjfEGLFllxfejLJjanZVRENsXhIxSWDgbvHHOAFtHzqdfquGbdQvOFlhDiWpxwEolxbep
fVfpKYGMNIQuOlmtTkNRDFTVMtVkEXYUDZKfEihbxXsSLGDcKSHSMXZxAturZVEQgismVAgMVVatqjBM
rXeHaGdccPJMlqhVAePDyEoIRTLCwJpkNTuOjEKEvXaAGhWmhWPHCBMVPkcPklbGIvzMzOFplRUsvZbE
vScmmoKktOUVOeKBcqVvoSsplqqssDvLiPqucbrxoNkodsbrZnvoDfyNGyUAURseEuJPUWsEiVCNcUNd
sxzoRVpEFuFloqWLumNVJITKXnWnOlGpCaQgTLJYizixXoxAHHbodRtPHBbnSzZRZOmlWKOQqvHWAhDh
cYBGRQsFwyesMILhiwjnvjeMIZnHYHYNrmOahjrVPuRgsxdfgUbKCZAVfcOizDeQLKiFQmQQUlDHnCQe
lMnlLSrtXhmGDqISCgElUrZXbXjGGkdWadBbxzVojGQwyhAbWMhSKFFwoIqJfIDdZjUdfCYFkpDdIuWe
aFIUFhnlsREthBRoaquSzBVVOPABfuAYZpoalZwNfZMPOptcoQYVUdRYlXuYChPAdRJgFgwPyTszSXIe
qHRtMxyNlPGoBfpjxHnNvwIADmJmquLgMQGtpJAyvflZjFwAgIymerCTnVkjvqPKFVRscOqAhqvCqCjw
BBojzXKIdphOVTFKhBpnIWYRfuqvQZgVMaqNBkYKzqGaEnBFKZukSLdPbXNmcZtMeykLwlLbZqaHayOb
IWZvbxEXXnaozCHeyiYMnWqIAwJxhMIPDsgySMKhdBYmdrGdbJOfJralshwvhWlmatTsylewdimJEzph
tuTzSGOkGDPPvltRVJPdHRPBTAsKWncfjjuHdlEVOeZIvVnUFHmyGTFDlMGVyAIdzLocbTXIHYTopIok
UHFAVjEXPlsMoKTriyGnfeTlVzvGhVZzUAWWPdZNdIxKioQylFMJZmSToyRGsDJKJXQxPkINvmoHCVUc
RIjImkWWxTnDLQiXdmHqQrWBuvguUUubGByTRnJfkNWxsSupcfIVgboDWzqYHEfAnIKCfdYUOslfXPax
YnaJfNLqJgcxRjBmRpOYgNpZOpzMOCVIRiiXdIqqFxPJhQqJadKiCesOsZoWGWbbQSVRZUlbNZdzeUTE
nhdMSCKCPbpWZguZHGkLiWCisjqnaLbJpbRFAHPjGbHOXKZQXoQQZohmVqjTcdWNhXEjPlLKnjpwbMPQ
ybzDvGgkybXtbDmjQuyOrMrcYGRGGfuuPXzieaetSBidnSRPsLaXKGcxDkXmHbqMWZJXsQkwtojlxOeU
KSIFdVvNEnOUmIZDdlnwtJcPBlcpRWNTazpzgItwJotSLWZruzrMlSGASMWDwOqTpeYYHaTHCCurPdwB
AWzUtwblZXNrBYdjUoDacvmRVURqOzUPlnFISsZMFPtthnDHSsFgkYfsMtXFuNPhLTleWVrmelyFaemo
bVIhEAxNwOUDQCOCDIBHsQlFxCbHErKiBsvQNjuIGnIzZiwoVTdUZnucSaKdHrxJeGQfTawFJefGJFFa
GHzELfnGBmkZyorbbDDwhvEVeIYIGLPMEuZduqFjbeWbVfzVIRZNXwPLgcYUsevuhEQXfYcJshYnJaWz
iqvlswEBRKNYEJidlzdWnQJpBtyjHYVpkQGzdYkeREqjhmmnUIbGZVnwwaMKqgXfURSICNxdteUSGhGZ
UEEFhWRoTKGRwFmPpZPOsalsrNOlkTdXqGKoWlWkqJvYYrtLiTfhdItMbbhdumSYgCcQVUARnYFWkCsC
jElZxrQHIlbTHFLOnrutlvyxzaSIdkJgeyMUnUmtXfnaIedbAInAuQssOQqBTLbvFRiqKqUSdUEmcRmN
LvAxlgliymfbjTwDSqNTLcAEIerzpUShNKkuehciEAYeGJOFFcOvurJFUyfZhQqzfaneiBcrPhaphSCB
StQiJvtoPhHcLUbriDUIfifVFnNtJfGlmcbQJSXsZfVjpbqnkMllUmHzLvEuSarSlNlNHsWvYlfhjMEA
epYTjoRGZeAAtURFeDfDxTYmOmONuQQBdcdncFGjhHmKlwqmUWoXuIXIxaaXnNThgPGtIlynrUIPLQTG
xXhattDrfBGbZRveKbgjzxJLdYREQlMeLtcIEUoyJocdAfUbymxuFLVjGkOQniiPParqoyQYfDYAQTkM
WLicLxpEFkBbwlKrTyYilKTtYkpVGxtOjYmcBDOrwFhFiGutmpTyTarUbVUeSevBTdaPDpjRkaEmLJMg
WsMhSGfIcBChcqrRKgKpjvGnFipjswgjetRtniMagakbCXAjpzWTtMlgZGCJwGyglpcLebrKWhgwJfWV
qGifWNEpCtjuejHoyVCdIxzMYGnfoslgTNAJdtVBWDVoGLzHSAVBTnhNIvAOExQNiJOIPPiHkdaRbfaP
ixDDoCDOOeAqvQJFxLWDICfGmufyxmaMshbvcrtjqqVtffZTnbtCOQfzRMGwOQEKaAmSWjnYdNgvdkmd
dQmaKZSdqKNrnvJlcyVMKuNWmuoOeyKecgjXbmSqnpjwJEaDYoehEklEgJyiksGxdEKgfYRXQecRZgfe
qKWGc'''


countA = 0  # 统计前边的大写字母
countB = 0  # 统计小写字母
countC = 0  # 统计后边的大写字母
length = len(str1)

for i in range(length):
    if str1[i] == '\n':
        continue

    """
    |如果str1[i]是大写字母:
    |-- 如果已经出现小写字母:
    |-- -- 统计后边的大写字母
    |-- 如果未出现小写字母:
    |-- -- 清空后边大写字母的统计
    |-- -- 统计前边的大写字母
    """
    if str1[i].isupper():
        if countB:
            countC += 1
        else:
            countC = 0
            countA += 1

    """
    |如果str1[i]是小写字母:
    |-- 如果小写字母前边不是三个大写字母(不符合条件):
    |-- -- 清空所有记录,重新统计
    |-- 如果小写字母前边是三个大写字母(符合条件):
    |-- -- 如果已经存在小写字母:
    |-- -- -- 清空所有记录,重新统计(出现两个小写字母)
    |-- -- 如果该小写字母是唯一的:
    |-- -- -- countB记录出现小写字母,准备开始统计countC
    """
    if str1[i].islower():
        if countA != 3:
            countA = 0
            countB = 0
            countC = 0
        else: 
            if countB:
                countA = 0
                countB = 0
                countC = 0
            else:
                countB = 1
                countC = 0
                target = i

    """
    |如果前边和后边都是三个大写字母:
    |-- 如果后边第四个字母也是大写字母(不符合条件):
    |-- -- 清空记录B和C,重新统计
    |-- 如果后边仅有三个大写字母(符合所有条件):
    |-- -- 打印结果,并清空所有记录,进入下一轮统计
    """
    if countA == 3 and countC == 3:
        if i+1 != length and str1[i+1].isupper():
            countB = 0
            countC = 0
        else:
            print(str1[target], end='')
            countA = 3
            countB = 0
            countC = 0


运行结果:
================= RESTART: C:\Users\ThinkPad\Desktop\test.py =================
ilovefishc

猜你喜欢

转载自blog.csdn.net/qq_38721302/article/details/83045746