类型转换、字符串处理、正则、异常处理
1.类型转换：
#!/usr/bin/env python # -*- coding: utf-8 -*- #_______________________________str转list__________________________________________________ #########强制转换-不推荐 str1 = "12345" list1 = list(str1) print(list1) #########split切割转换-推荐 str2 = "123d sjhid dhi" ##默认以空格分割,也可指定符号或字母 list2 = str2.split() #or list2 = str2.split(" ") #list2 = str2.split('d')#指定字母分割 print (list2)
#_______________________________list转str___________________________________________________ list3=['chen','wei','25','popp123','hjdh'] ####默认list转到str-推荐 # str4 = "".join(list3) # print (str4) # ####每个元素用.隔开 # str5 = ".".join(list3) # print (str5) # ####每个元素用空格隔开 str6 = " ".join(list3) print(str6) #########list转str import json promotion_ids_list=["123","chenwei"] #把list转成str promotion_ids = json.dumps(promotion_ids_list) print(type(promotion_ids)) #使用str也可以把list转成str aa=str(promotion_ids) print(type(aa))
#________________________________list转dict_________________________________________________ ####两个list转dict list1 = ['key1','key2','key3'] list2 = ['1','2','3'] print(dict(zip(list1,list2))) ####将嵌套list转为dict-方式1 new_list= [['key1','value1'],['key2','value2'],['key3','value3']] print(dict(new_list)) ####将嵌套list转为dict-方式2 new_list= [['key1','value1'],['key2','value2'],['key3','value3']] new_dict = {} for i in new_list: new_dict[i[0]] = i[1] #i也是一个字典 print(new_dict)
#________________________________dict转list_____________________________________________________ ###把一个字典拆成一个list或两个list或嵌套list d={1:"a",2:"b",3:"c"} result=[]#存放key和value的list res=[] ree=[]#嵌套list for key,value in d.items(): res.append(key)#把key追加到res result.extend([key,value])#把key，value同时追加到result（） ree.append([key,value])#把key追加到res print('result:',result) print('res:',res) print('ree:',ree) ###dict转list-方式二 d1={1:"a",2:"b",3:"c"} #list_keys= [ i for i in d1.keys()]#把key转成list list_values = [i for i in d1.values()]#把valus转成list print(list_values) ###dict转list-方式三 a = {'a' : 1, 'b': 2, 'c' : 3} #字典中的key转换为列表 key_value = list(a.keys())#也可以values() print('字典中的key转换为列表：', key_value) #________________________dict转str_____________________________________________________________ import json b = {'a' : 1, 'b': 2, 'c' : 3} bb=json.dumps(b) print(type(bb)) print(bb) #__________________________str转dict___________________________________________________________ b1='{"a": 1, "b": 2, "c": 3}' ####通过loads print(type(b1)) b11=json.loads(b1) print(type(b11)) ###通过eval b22=eval(b1) print(type(b22)) print(b22) #___________________________ bytes和str相互转换___________________________________________________ # bytes对象 b = b"example" # str对象 s = "example" #方式一 # str 转 bytes sb = bytes(s, encoding = "utf8") print(sb) # bytes 转 str bs = str(b, encoding = "utf8") print(bs) # 方式二 # str 转 bytes sb2 = str.encode(s) print(sb2) # bytes 转 str bs2 = bytes.decode(b) print(bs2)
2.正则匹配：
#!/usr/bin/env python # encoding: utf-8 import re ###_________________________________________findall表达式________________________________________________ ''' findall:在字符串中找到正则表达式所匹配的所有子串，并返回一个列表，如果没有找到匹配的，则返回空列表 ''' def chen(): a=12 b='20' ff=['5','99','dd'] e='heheh123' dd="chen123.ll" d=5 print("函数内部") rr=re.findall(r"eh(.+)",e) print(rr) a=chen() ###匹配字符串中数字 a='九州379服' aa=re.findall(r'\d+',a)#从we匹配 print(aa) print(aa[0]) ####匹配we开始的字符 bb=re.findall('we(.*)','d*T#we12345678')#从we匹配 print(bb) ###字母 bb1=re.findall(r'[A-Za-z]+','d*T#we12345678')#从we匹配 print(bb1) #####区间匹配 text = "Find all matches in this text" matches = re.findall(r'\ball (.*?) this\b', text) print("指定开头结尾匹配中间数据:",matches) matches = re.findall(r'\bma\w+', text) print("匹配开头ma结尾为数字字母下划线:",matches) ###匹配wifi名称 aa=''' iface=wlan0 ident=[{type=WIFI, subType=COMBINED, networkId=Dalan_guest22}] iface=wlan0 ident=[{type=WIFI, subType=COMBINED, networkId=Dalan_guest}] ident=[{type=WIFI, subType=COMBINED, networkId=Dalan_guest}] uid=-1 set=ALL tag=0x0 ident=[{type=WIFI, subType=COMBINED, networkId=Dalan_guest}] uid=-1 set=ALL tag=0x0 ''' text=re.findall('networkId=(.*)}',aa)#从networkId=匹配到 }结束 print(text) #____________________________________sub表达式________________________________________________________ ''' sub:过滤匹配到的字符串 ''' a=re.sub(r'\d', "", "abc34*%d")#过滤匹配到的字符串 b=re.sub(r'\d', "adc", "abc34*%d")#用adc替换匹配的字符 print(b) phone = "2004-959-559 # 这是一个电话号码" # 删除注释 num = re.sub(r'#.*$', "", phone) print ("电话号码 : ", num) # 移除非数字的内容 num = re.sub(r'\D', "", phone) print ("电话号码 : ", num) #_____________________________________________match_____________________________________________ ''' match 尝试从字符串的起始位置匹配一个模式，如果不是起始位置匹配成功的话，match()就返回None。 re.match只匹配字符串的开始，如果字符串开始不符合正则表达式，则匹配失败，函数返回None ''' print(re.match(r'^www', 'www.baidu.com').span())#匹配www,在起始位置匹配 print(re.match(r'^ww', 'www.baidu.com').span())#匹配ww,在起始位置匹配 print(re.match(r'^www', 'www.baidu.com'))#匹配www，# 不在起始位置匹配 print(re.match("\d{1,3}","10086"))#匹配100 print(re.match("\D{1,3}","10086"))#匹配失败了 aa=re.match("\D{1,4}","chenwei10086")#匹配chen print(aa) #打印匹配结果 print('111',aa.group()) print(aa[0]) ###match匹配url前缀 apk_link="http://file.superdalan.com/6cf5700f1a8e" apk=re.match(r'^https?:/{2}file.superdalan.com.+$', apk_link) print(apk.group(0)) #注意：？可以匹配0次，及向左移位一次(可匹配http及https) #________________________________________________search表达式_____________________________________________________ ''' # re.match与re.search的区别：re.match只匹配字符串的开始，如果字符串开始不符合正则表达式，则匹配失败，函数返回None；而re.search匹配整个字符串，直到找到一个匹配。 ''' ###可以匹配成功的 res = re.search("python","Life is short. I learn python!") print(res) print(res.group())#匹配表达式 print(res.string) #匹配字符串 ###匹配失败的 res = re.search("java","Life is short. I learn python!") print(res) ###输出匹配位置和原配字符串 res = re.search("python","Life is short. I learn python!") print(res.start()) #匹配字符串的开始位置 print(res.end()) #匹配字符串的结束位置 print(res.span()) #匹配字符串的元组(开始位置+结束位置) print(res.string) #匹配字符串 ###search匹配案例 str = 'response body:{"name":"张三","age":20,"Idcard_no":"4100058971","phone":"15011100001"}' res = re.search("{.*?}",str) #万能的.*? print(res) print(res.group()) #或者print(res[0]) ###search匹配案例2 import re aa="""__GetZoneResult_ = { mts:'1597557', province:'广东', catName:'中国移动', telString:'15975579874', carrier:'广东移动' }""" match = re.search(r"province:'(.*?)'", aa) carrier = match.group(1) res = carrier if carrier else "未找到匹配的结果" print(res)
3.遍历字符串的4中方式：
girl_str = "love You" # ##通过for in的方式 for i in girl_str: print(i) # ##内置函数iter()遍历 for every_char in iter(girl_str): print(every_char) ##内置函数enumerate()遍历 for index, every_char in enumerate(girl_str): #print(str(index) + every_char) #print(every_char) print(str(every_char)) #通过range遍历 for i in range(len(girl_str)): print(girl_str[i])
4.字符串判断&包含&为空：
# __________________判断字符串值是否相等_______________ if string1 == string2: print("字符串值相等") else: print("字符串值不相等") # ___________________判断字符串长度____________________ if len(string1) > len(string2): print("string1个数,大于string2") elif len(string1) < len(string2): print("string1个数,小于string2") else: print("string1个数,等于string2个数") # ____________________字符串包含______________________ if "He" in string1: print("string1包含He") # 查找字符串并返回位置,没找到就返回-1 print(string1.find("llo")) # 魔法方法判断字符串包含xx字符,返回Ture或False print(string1.__contains__("llo")) # 正则方式判断字符串包含xx字符,返回Ture或False import operator print(operator.contains("hellopython", "llo")) #_______________________字符串为空判断__________________________________ aa=""; #方法一 if not aa: print("字符串为空1") #方法二 if len(aa)<=0: print("字符串为空2") #方法三 print(bool(aa)) #检测字符串是否只由空格组成 print(aa.isspace()) #去两边空格str.strip() #去左空格：str.lstrip() #去右空格：str.rstrip()
5.异常处理：
#!/usr/bin/env python # -*- coding: utf-8 -*- ##_____________________________________try与except和else执行顺序________________________________________ try: print('正常执行'+'333') except: print('异常时执行') else: print('语句异常后不执行')#else和try一起的 ###_______________________________try与except和finally执行顺序___________________________________________ try: print(111111111) except: print('异常时执行') finally: print('无论语句是否异常都会执行') ####__________________________________函数：一个try对应多个 except_______________________________________________ def all(sstr): try: if sstr=='chenwei': print('正常执行:'+sstr) elif sstr==520: print('正常执行:'+sstr) elif sstr == '大蓝游戏': sstr=int(sstr) elif sstr == 'test': print(aa)#引用未定义的变量aa,故意引发异常 elif sstr ==100: print(len()) except TypeError: print('数据类型异常') except ValueError: print('数据值错误') except: print('默认异常-如果上面异常不存在就报此异常') else: print('语句异常后不执行')#else和try一起的 #all('chenwei')#正常的 #all(520)#数据类型异常 all('大蓝游戏')#数据值错误 all('test')#定义的异常类没有捕获到，就走默认异常 ##________________________________________一个try对应多个 except___________________________________________________ chen='testeee' try: if chen=='chen123': print('正常执行:'+sstr)#变量未定义,,故意引发异常) elif chen == 'test': print(chen+555)#数据类型异常 elif chen !=100: print('1111') print(chen.sort())#没有捕获到就显示万能异常 except ValueError: print('数据值错误') except NameError: print('变量类型错误') except: print('万能异常') ##________________________________________一个try对应多个 except___________________________________________________ chen = 'test' chen1 = 'chen123' chen2=['dalan','test','123'] chen3={'name':'dalan_ganme','age':'105'} try: #print('正常执行:' + sstr) # 变量未定义,,故意引发异常) #索引错误 #print(chen[5]) #序列中没有此索引、越界错误 #print(chen1[10]) #没有此索引、越界错误 #key错误 print(chen3['test']) #打印不存在的key except ValueError: print('数据值错误') except NameError: print('变量类型错误') except KeyError as e: print('捕获到一个Key值错误:'，e) except IndexError as e: print('捕获一个索引值错误') except TypeError: print('对类型无效的操作') except: print('万能异常') ###____________________________________自定义异常自定义类型__________________________________________________________ #自定义异常类型必须继承Exception___ class chen_error(Exception):#注意：自定异常类型必须继承Exception def __init__(self,name): self.name=name def chen(self,age): print(age) try: if age > 20: raise chen_error("自定义异常") else: print(self.name) except chen_error as e: print(e)#打印异常 ddd=chen_error('chenwei') ddd.chen(52) ###___________________________________________自定义异常raise________________________________________________________ #chen='大蓝游戏' chen=['abcd','chenwei'] try: if isinstance(chen,str): print('chen的类型是:str') else: raise Exception("chen变量类型错误")#默认为 Exception except Exception as e: print(e) ###___________________________________________自定义异常raise________________________________________________________ try: a = input("输入一个数：") if(not a.isdigit()): raise ValueError("a 必须是数字") except ValueError as e: print("引发异常：",repr(e)) #重新报异常 raise try: a = input("输入一个数：") print(type(a)) if(not a.isdigit()):#isdigit检测字符串是否只由数字组成 raise RuntimeError('自定义异常,触发except RuntimeErro')#触发except 下的RuntimeErro if isinstance(a,str): print('44444444444') print(a+56)#这里a是字符串 except RuntimeError as e: print("这里引发异常：",repr(e)) except: print('当没有捕获到就走万能异常')
两种异常处理的写法：
try: print('第一层try') try: print('第二层try')##当第二层try没有异常时,就不走第二层except print('正常执行'+'333') print('异常执行' + '333'+2226) #写成异常(就会触发第二层except) except: print('第二层except') print('异常时执行1111111111111'+333) #写成异常(就会触发第一层except) except: print('第一层except') else: print('没有异常时才执行') try: print('第一层try') print('正常执行' + '333') print('异常执行'+'333'+22)#触发异常 except: try: print('第二层try') print('正常执行1111111111111' ) #print('异常时执行1111111111111'+333) #触发第二层except except: print('第二层except') else: print('第二层try正常时,才执行该语句') else: print('第一层try正常时,才执行该语句')
连接地址：
https://blog.csdn.net/weixin_43158056/article/details/92798114 .................字符串常用操作 ，，正则测试工具带生成python代码
https://www.jb51.net/article/47956.htm .......................................................字符串常用函数操作
https://www.cnblogs.com/twelvezuo/p/11727634.html ................................字符串常用函数操作2
https://blog.csdn.net/crq_zcbk/article/details/81103595 .............................python异常处理，python标准异常类型
https://mp.weixin.qq.com/s/s1YXeV0tBjaoBp8Yjpngpg ..............................字符串100钟处理方法
