Python中常见的字符串的操作方法:
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常用字符串的操作方法:
1,str.capitalize()#首字母大
print(name.capitalize())
name = "my name is Span!"
print(name.capitalize())
###
My name is span!
2,str.upper(); str.lower() #全部变成大写;全部变成小写
#需求分析:在证输入码时,不区分大小写 s_str = "aWIo8" user_input = input("请输入验证码:") if s_str.upper() == user_input.upper(): print("输入成功!")
else:
print("请重新输入验证码!")
#字符串操作方法对数字不敏感
3.print(name.swapcase()) #大小写翻转
4.print(msg.title()) #每个单词的首字母大写或者用特殊字符和数字隔开的
1.msg = "span ygen lijing" print(msg.title())
>>>Span Ygen Lijing
2.msg = "span&ygen&lijing" print(msg.title())
>>>Span&Ygen&Lijing
5.str.center(width,[,fillchar]) #字符串居中函数;默认的是空白填充物
#str.center() name = "span" print(name.center(20,"$")) >>>$$$$$$$$span$$$$$$$$
6.str.count(sub[,start][,end]) #数字符串中的元素出现的个数,统计元素的个数。若没有返回0
#str.count() name = "span ygen lijing" print(name.count("n")) >>>3 ()一共出现了3个"n"
7.#\t前面的补全
# 默认将一个tab键变成8个空格,如果tab前面的字符长度不足8个,则补全8个,如果tab键前面的字符长度超过8个不足16个则补全16个,以此类推每次补全8个。
str_tab = str.expandtabs()
print(str_tab)
#str.expandtabs() str_tab = "span\tlijing" print(str_tab.expandtabs()) >>>span lijing
8.#通用方法,返回字符串、元组、列表、字典等元素的个数
len(str)
9.#startswith 判断是否以...开头
#endswith 判断是否以...结尾
python_study = "Span is study python program.... " str_judge = python_study.startswith("Span") print(str_judge) >>>True (返回bool值)
if str_judge:
pass
elif python_study.startswith("Span"):
pass
else:
pass
#通过切片操作判某个元素是否在字符串中 顾头不顾尾
#str.startswith() str_me = "span ygen!" judge_me = str_me.startswith("an",2) # 设定字符串从索引2开始到最后 print(judge_me) >>>True
10. str.find()寻找字符串中的元素是否存在;若元素存在返回的找到的元素的索引,如果找不到返回-1
#str.find() name = "span" prnt(name.find("a")) >>>2
11. str.index()返回的找到的元素的索引,找不到报错。
name = "span ygen lijing" print(name.index("a")) >>>2
12. str.strip([chars]) 在其左侧和右侧去除掉chars中列出的字符。若没有chars,默认的是去除空格(只能去除前后的chars)
另外还有两个衍生方法:str.lsrip():只删左边;str.rsrip():只删右边;
#str.strip() user_name = input("请输入您的用户名:").strip() if user_name == "span": print("输入正确!")
#只能去除两边的字符 name = "%span*" print(name.strip("*%")) >>>span
13. str.split()分割文本 split 以什么分割,最终形成一个列表此列表不含有这个分割的元素。(字符串转换成列表 str---->list)msg = "span, ygen, lijing"
print(msg.rsplit(",")) >>>['span', ' ygen', ' lijing'] msg = "span, ygen, lijing"
print(msg.rsplit("n",1)) >>>['span, ygen, liji', 'g']
14. str.format 的三种玩法 格式化输出
#str.format() 1:msg = "我叫{};今年{};爱好{}.....再说一遍我叫{}".format("span",25,"Python","span") print(msg) >>>我叫span;今年25;爱好Python.....再说一遍我叫span 2: name = input("请输入您的名字:") msg = "我叫{0};今年{0};爱好{2}.....再说一遍我叫{0}".format(name,25,"Python") print(msg) >>>我叫span;今年25;爱好Python.....再说一遍我叫span 3.msg = "我叫{name};今年{age};爱好{hobby}.....再说一遍我叫{name}".format(name="span",age=25,hobby="Python") print(msg) >>>我叫span;今年25;爱好Python.....再说一遍我叫span
15. str.replace() 替换
#str.replace() study_me = "My name is span, I am studying Python! " print(study_me.replace("span","wo")) >>>My name is wo, I am studying Python! 默认是全部替换
16.str.is***()
print(str.isalnum()) #字符串由字母或数字组成
print(str.isalpha()) #字符串只由字母组成
print(str.isdigit()) #字符串只由数字组成
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