python基础-数据类型转换、字符串

str方法

string的方法如下：

1. str[索引]
2. 某起始位置按步长切片（正切、倒切）
3. 某起始位置是否以某某开头、结尾
4. 某起始位置包含某个字符的个数
5. 某起始位置find、index获取角标
6. strip、lstrip、rstrip去除某字符
7. split按某字符切割为几段
8. replace替换某字符或某字符片段几次
9. format格式化三种方法
10. 字符串构成

str截取

str = "helloPython"print(str[1])#含头不含尾,要取出的末尾索引+1print(str[0:5])#索引超出不报错print(str[5:11])print(str[5:2000])print(str[5:])#步长为2，中间隔1个取出来print(str[0:5:2])print(str[-1])#含头不含尾，取不到索引0print(str[3:0:-1])print(str[3::-1])print(str[-1:-5:-1])

输出如下：

E:\python\python_sdk\python.exe E:/python/py_pro/safly.pyehelloPythonPythonPythonhlonllellehnohtProcess finished with exi` code 0

str方法

str = "helloPython"#首字母大写，其他的都小写print(str.capitalize())print(str.upper())print(str.lower())print(str)print(str.swapcase())str = "hello python"print(str.title())#内同居中，总长度，空白处填充print(str.center(20))print(str.center(20,"*"))print(str.startswith("hh"))#截取的切片是否以h开头print(str.startswith("h",0,3))#是不是以o结尾的切片print(str.endswith("o",-3,-1))print(str.count("v"))#截取的切片包含h的个数,找不到返回0print(str.count("h",0,3))#find获取下标,找不到返回-1print(str.find("h"))print(str.find("h",2,5))print(str.index("h"))#找不到会报错# print(str.index("h",2,5))str = " hello python "#去除两边的空格print(str.strip())print(str.lstrip())print(str.rstrip())str = "hello python"#去除两边的hestr = "hello pythonhe"print(str.strip("he"))print("---")str = "titletitle"sp = str.split("t")#['', 'i', 'le'] 分割成一个列表print(sp)print(str.split("t",2))print(str.split("t",20))str = "hello python"print(str.replace("he","oo",1))temp = str.replace(str,"jljle")print("-------------------")print(temp)name='jinxin123'print(name.isalnum()) #字符串由字母或数字组成print(name.isalpha()) #字符串只由字母组成print(name.isdigit()) #字符串只由数字组成#format的三种玩法 格式化输出res='name:{},age:{},sex:{}'.format('egon',18,'male')print(res)res='name:{1},age: {0} ,sex:{1}'.format('egon',18,'male')print(res)res='name:{name} ,age:{age} ,sex:{sex}'.format(sex='male',name='egon',age=18)print(res)

输出如下：

E:\python\python_sdk\python.exe E:/python/py_pro/demo.pyHellopythonHELLOPYTHONhellopythonhelloPythonHELLOpYTHONHello Python    hello python    ****hello python****FalseTrueTrue010-10hello pythonhello python  hello pythonllo python---['', 'i', 'le', 'i', 'le']['', 'i', 'letitle']['', 'i', 'le', 'i', 'le']oollo python-------------------jljleTrueFalseFalsename:egon,age:18,sex:malename:18,age: egon ,sex:18name:egon ,age:18 ,sex:maleProcess finished with exit code 0

bool、int、str转换

"""    二进制  十进制    0000 0001  1    0000 0010  2    0000 0011  3    0000 0100  4    0000 0101  5    0000 0110  6""""""二进制的占位长度"""i = 3j = 6k = 8print(i.bit_length())print(j.bit_length())print(k.bit_length())"""字符串 bool转换非空字符串都是True"""print(bool("sss"))print(bool("a"))print(bool("1"))print(bool(""))a = str(True)b = str(False)print(type(a))print(type(b))"""bool与int转换"""print(True or 1)print(True and 1)

输出如下：

E:\python\python_sdk\python.exe E:/python/py_pro/safly.py234TrueTrueTrueFalse<class 'str'><class 'str'>True1Process finished with ex`t code 0