字符串的方法1
1 .首字母大写
# test = "aLex" # v = test.capitalize() # print(v)
2 所有变小写，casefold更牛逼，很多未知的对相应变小写
# v1 = test.casefold() # print(v1) # v2 = test.lower() # print(v2)
3 设置宽度，并将内容居中
# 20 代指总长度 # * 空白未知填充，一个字符，可有可无 # v = test.center(20,"中") # print(v) # test = "alex" # v = test.ljust(20,"*") # print(v) # test = "alex" # v = test.rjust(20,"*") # print(v) # test = "alex" # v = test.zfill(20) # print(v)
4 .去字符串中寻找，寻找子序列的出现次数
# test = "aLexalexr" # v = test.count('ex') # print(v) # test = "aLexalexr" # v = test.count('ex',5,6) # print(v)
5.以什么什么结尾
以什么什么开始
# test = "alex" # v = test.endswith('ex') # v = test.startswith('ex') # print(v)
6.expandtabs,断句20，
# test = "username\temail\tpassword\nlaiying\tying@q.com\t123\nlaiying\tying@q.com\t123\nlaiying\tying@q.com\t123" # v = test.expandtabs(20) # print(v)
7 .从开始往后找，找到第一个之后，获取其未知
# > 或 >= # test = "alexalex" # 未找到 -1 # v = test.find('ex') # print(v)
8. index找不到，报错 忽略
# test = "alexalex" # v = test.index('8') # print(v)
9. 格式化，将一个字符串中的占位符替换为指定的值
# test = 'i am {name}, age {a}' # print(test) # v = test.format(name='alex',a=19) # print(v) # test = 'i am {0}, age {1}' # print(test) # v = test.format('alex',19) # print(v)
10. 格式化，传入的值 {"name": 'alex', "a": 19}
# test = 'i am {name}, age {a}' # v1 = test.format(name='df',a=10) # v2 = test.format_map({"name": 'alex', "a": 19})
# v3 =test.format(**{'name':'alex','a':19})
11. 字符串中是否只包含 字母和数字
# test = "123" # v = test.isalnum() # print(v) # str
12. 是否是字母，汉子
# test = "as2df" # v = test.isalpha() # print(v)
13. 当前输入是否是数字
# test = "二" # 1，② # v1 = test.isdecimal() # v2 = test.isdigit() # v3 = test.isnumeric() # print(v1,v2,v3)
14. 是否存在不可显示的字符
# \t 制表符 # \n 换行 # test = "oiuas\tdfkj" # v = test.isprintable() # print(v)
15. 判断是否全部是空格
# test = "" # v = test.isspace() # print(v)
16. 判断是否是标题
# test = "Return True if all cased characters in S are uppercase and there is" # v1 = test.istitle() # print(v1)
转换为标题即全部大写 # v2 = test.title() # print(v2)
# v3 = v2.istitle() # print(v3)
17. ***** 将字符串中的每一个元素按照指定分隔符进行拼接
# test = "你是风儿我是沙" # print(test) # # t = ' ' # v = "_".join(test) # print(v)
18. 判断是否全部是大小写 和 转换为大小写
# test = "Alex" # v1 = test.islower() # v2 = test.lower() # print(v1, v2) # v1 = test.isupper() # v2 = test.upper() # print(v1,v2)
19.# 移除指定字符串
# 有限最多匹配 # test = "xa" # # v = test.lstrip('xa') # v = test.rstrip('9lexxexa') # # v = test.strip('xa') # print(v) # test.lstrip() # test.rstrip() # test.strip() # 去除左右空白 # v = test.lstrip() # v = test.rstrip() # v = test.strip() # print(v) # print(test) # 去除\t \n # v = test.lstrip() # v = test.rstrip() # v = test.strip() # print(v)
20. 对应关系替换（下面是12345替换屌aeiou）
# test = "aeiou" # test1 = "12345" # v = "asidufkasd;fiuadkf;adfkjalsdjf" # m = str.maketrans("aeiou", "12345") 创建对应关系 # new_v = v.translate(m) # print(new_v)
21. 分割为三部分，分隔符保留
# test = "testasdsddfg" # v = test.partition('s')从左开始分割
# print(v)
# v = test.rpartition('s')从右开始分割
# print(v)
22. 分割为指定个数，不保留分隔符
# v = test.split('s',2) # print(v) # test.rsplit()
23 分割，只能根据，true，false：是否保留换行
# test = "asdfadfasdf\nasdfasdf\nadfasdf" # v = test.splitlines(False) # print(v)
24 .判断是否以xxx开头，以xx结尾
# test = "backend 1.1.1.1" # v = test.startswith('a') # print(v) # test.endswith(‘a’)
25 .大小写互换
# test = "aLex" # v = test.swapcase() # print(v)
26.字母，数字，下划线 ： 标识符 def class
# a = "def" # v = a.isidentifier() # print(v)
27. 将指定字符串替换为指定字符串
# test = "alexalexalex" # v = test.replace("ex",'bbb') # print(v) # v = test.replace("ex",'bbb',2) # print(v)
###################### 7个比较常用的方法 ######################
# join # '_'.join("asdfasdf")
# split
# find
# strip
# upper
# lower
# replace
