[{"data":1,"prerenderedAt":59},["ShallowReactive",2],{"article-9":3},{"code":4,"msg":5,"data":6,"count":14},200,"查询成功",{"id":7,"title":8,"keywords":9,"description":10,"category_id":11,"content":12,"body_html":13,"thumb_up":14,"clicks":15,"sort":14,"remark":16,"status":17,"is_open":17,"is_deleted":14,"is_top":14,"is_recommend":17,"create_time":18,"update_time":19,"image_id":20,"url":13,"member_id":14,"cate_name":21,"prev":22,"next":25,"tags":28,"words":31,"read_time":26,"comments":14,"cover":32,"relevant":33},9,"Python整理之字符串操作","python,字符串","字符串是 Python 中最常用的数据类型。我们可以使用引号('或\")来创建字符串。创建字符串很简单，只要为变量分配一个值即可。",5,"如有字符串 `mystr = 'I am learning python string operation python.'`，以下是常见的操作\n\n1、find\n\n语法：\n\n```python\nmystr.find(str, start=0, end=len(mystr))\n```\n检测 str 是否包含在 mystr中，如果是返回开始的索引值，否则返回-1\n\n实例：\n\n```python\nprint(mystr.find('Python'))#14\nprint(mystr.find('Python', 0, 10))#-1\n```\n\n2、rfind\n\n类似于find()函数 ，不过是从右边开始查找\n\n```python\nmystr.rfind(str, start=0,end=len(mystr))\n```\n实例：\n\n```python\nprint(mystr.rfind('python'))#38\nprint(mystr.rfind('python', 0, 10))#-1\n```\n\n3、index\n\n跟find()方法一样，只不过如果str不在 mystr中会报一个异常.\n\n```python\nmystr.index(str, start=0, end=len(mystr))\n```\n实例：\n\n```python\nprint(mystr.index('Python', 0, 10))\n```\n异常：\n\n```python\nTraceback (most recent call last):\n  File \"i:\u002FPython学习\u002F字符串str.py\", line 5, in \n    print(mystr.index('Python', 0, 10))\nValueError: substring not found\n```\n4、rindex\n\n类似于 index()，不过是从右边开始.\n\n```python\nmystr.rindex( str, start=0,end=len(mystr))\n```\n实例：\n\n```python\nprint(mystr.rindex('Python', 0, 10))\n```\n异常：\n\n```python\nTraceback (most recent call last):\n  File \"i:\u002FPython学习\u002F字符串str.py\", line 6, in \n    print(mystr.rindex('Python', 0, 10))\nValueError: substring not found\n```\n5、count\n\n返回 str在start和end之间 在 mystr里面出现的次数\n\n```python\nmystr.count(str, start=0, end=len(mystr))\n```\n实例：\n\n```python\nprint(mystr.count('on'))#3\n```\n6、replace\n\n把 mystr 中的 str1 替换成 str2,如果 count 指定，则替换不超过 count 次.\n\n```python\nmystr.replace(str1, str2,  mystr.count(str1))\n```\n实例：\n\n```python\nprint(mystr.replace('python', 'Python', mystr.count('python')))\n```\n结果：\n\n```python\nI am learning Python string operation Python.\n```\n7、split\n\n```python\nmystr.split(str=\"\", num=string.count(str))\n```\n以 str 为分隔符切片 mystr，如果 num 有指定值，则仅分隔 num 个子字符串\n\n实例：\n\n```python\nprint(mystr.split(' '))\nprint(mystr.split(' ', 2))\n```\n结果：\n\n```python\n['I', 'am', 'learning', 'python', 'string', 'operation', 'python.']\n['I', 'am', 'learning python string operation python.']\n```\n8、capitalize\n\n```python\nmystr.capitalize()\n```\n把字符串的第一个字符大写\n\n实例：\n\n```python\nmystr = 'i am learning python string operation python.'\nprint(mystr.capitalize())\n```\n结果：\n\n```python\nI am learning python string operation python.\n```\n9、title\n\n```python\nmystr.title()\n``````python\n把字符串的每个单词首字母大写\n\n实例：\n\n```python\nprint(mystr.title())\n```\n结果：\n\n```python\nI Am Learning Python String Operation Python.\n```\n10、startswith\n\n```python\nmystr.startswith(obj)\n```\n检查字符串是否是以 obj 开头, 是则返回 True，否则返回 False\n\n实例：\n\n```python\nprint(mystr.startswith('I'))\nprint(mystr.startswith('i'))\n```\n结果：\n\n```python\nTrue\nFalse\n```\n11、endswith\n\n```python\nmystr.endswith(obj)\n```\n检查字符串是否以obj结束，如果是返回True,否则返回 False\n\n实例：\n\n```python\nprint(mystr.endswith('python.'))\nprint(mystr.endswith('Python.'))\n```\n结果：\n\n```python\nTrue\nFalse\n```\n12、lower\n\n```python\nmystr.lower()  \n```\n转换 mystr 中所有大写字符为小写\n\n实例：\n\n```python\nmystr = 'I AM LEARNING PYTHON STRING OPERATION PYTHON.'\nprint(mystr.lower())\n```\n结果：\n\n```python\ni am learning python string operation python.\n```\n13、upper\n\n```python\nmystr.upper() \n```\n转换 mystr 中的小写字母为大写\n\n实例：\n\n```python\nmystr = 'i am learning python string operation python.'\nprint(mystr.upper())\n```\n结果：\n\n```python\nI AM LEARNING PYTHON STRING OPERATION PYTHON.\n```\n14、ljust\n\n```python\nmystr.ljust(width)\n```\n返回一个原字符串左对齐,并使用空格填充至长度 width 的新字符串\n\n实例：\n\n```python\nmystr = 'Hello'\nprint(len(mystr))\nprint(len(mystr.ljust(10)))\n```\n结果：\n\n返回字符串长度可明显看出效果\n\n```python\n5\n10\n```\n15、rjust\n\n```python\nmystr.rjust(width)  \n```\n返回一个原字符串右对齐,并使用空格填充至长度 width 的新字符串\n\n实例：\n\n```python\nmystr = 'Hello'\nprint(mystr.rjust(10))\nprint(len(mystr.rjust(10)))\n```\n结果：\n\n```python\n     Hello\n10\n```\n16、center\n\n```python\nmystr.center(width)  \n```\n返回一个原字符串居中,并使用空格填充至长度 width 的新字符串\n\n实例：\n\n```python\nmystr = 'Hello'\nprint(mystr.center(25))\n```\n结果：\n\n```python\n           Hello\n```\n17、lstrip\n\n```python\nmystr.lstrip()\n```\n删除 mystr 左边的空白字符\n\n实例：\n\n```python\nmystr = '    Hello    '\nprint(mystr.lstrip())\n```\n结果：\n\n```python\nHello\n```\n18、rstrip\n\n```python\nmystr.rstrip()    \n```\n删除 mystr 字符串末尾的空白字符\n\n实例：\n\n```python\nmystr = '    Hello    '\nprint(mystr.rstrip())\n```\n结果：\n\n```python\n    Hello\n```\n19、strip\n\n```python\nmystr.strip()\n```\n删除mystr字符串两端的空白字符\n\n实例：\n\n```python\nmystr = '    Hello    '\nprint(mystr.strip())\n```\n结果：\n\n```python\nHello\n```\n20、partition\n\n```python\nmystr.partition(str)\n```\n把mystr以str分割成三部分,str前，str和str后\n\n实例：\n\n```python\nmystr = 'i am learning python string operation python.'\nprint(mystr.partition('string'))\n```\n结果：\n\n```python\n('i am learning python ', 'string', ' operation python.')\n```\n21、rpartition\n\n```python\nmystr.rpartition(str)\n```\n类似于 partition()函数,不过是从右边开始.\n\n实例：\n\n```python\nmystr = 'i am learning python string operation string python.'\nprint(mystr.rpartition('string'))\n```\n结果：\n\n```python\n('i am learning python string operation ', 'string', ' python.')\n```\n22、splitlines\n\n```python\nmystr.splitlines()  \n```\n按照行分隔，返回一个包含各行作为元素的列表\n\n实例：\n\n```python\nmystr = 'i am learning python \\nstring operation string python.'\nprint(mystr.splitlines())\n```\n结果：\n\n```python\n['i am learning python ', 'string operation string python.']\n```\n23、isalpha\n\n```python\nmystr.isalpha()  \n```\n如果 mystr 所有字符都是字母 则返回 True,否则返回 False\n\n实例：\n\n```python\nmystr = 'Hello'\nprint(mystr.isalpha())\nmystr = '12345'\nprint(mystr.isalpha())\nmystr = 'abc 123'\nprint(mystr.isalpha())\n```\n结果：\n\n```python\nTrue\nFalse\nFalse\n```\n24、isdigit\n\n```python\nmystr.isdigit()\n```\n如果 mystr 只包含数字则返回 True 否则返回 False.\n\n实例：\n\n```python\nmystr = 'Hello'\nprint(mystr.isdigit())\nmystr = '12345'\nprint(mystr.isdigit())\nmystr = 'abc 123'\nprint(mystr.isdigit())\n```\n结果：\n\n```python\nFalse\nTrue\nFalse\n```\n25、isalnum\n\n```python\nmystr.isalnum()  \n```\n如果 mystr 所有字符都是字母或数字则返回 True,否则返回 False\n\n实例：\n\n```python\nmystr = 'Hello'\nprint(mystr.isalnum())\nmystr = '12345'\nprint(mystr.isalnum())\nmystr = 'abc123'\nprint(mystr.isalnum())\nmystr = 'abc 123'\nprint(mystr.isalnum())\n```\n结果：\n\n```python\nTrue\nTrue\nTrue\nFalse\n```\n26、isspace\n\n```python\nmystr.isspace()   \n```\n如果 mystr 中只包含空格，则返回 True，否则返回 False.\n\n实例：\n\n```python\nmystr = 'Hello'\nprint(mystr.isspace())\nmystr = ''\nprint(mystr.isspace())\nmystr = ' '\nprint(mystr.isspace())\nmystr = 'abc 123'\nprint(mystr.isalnum())\n```\n结果：\n\n```python\nFalse\nFalse\nTrue\nFalse\n```\n27、join\n\n```python\nmystr.join(str)\n```\nmystr 中每个字符后面插入str,构造出一个新的字符串\n\n实例：\n\n```python\nstr = ' '\nli = ['I', 'am', 'learning', 'python', 'string', 'operation', 'python.']\nprint(str.join(li))\nstr = '_'\nprint(str.join(li))\n```\n结果：\n```python\nI am learning python string operation python.\nI_am_learning_python_string_operation_python.\n```\n \n",null,0,541,"",1,"2019-01-17 22:14:51","2026-04-19 10:49:21",128,"Python",{"id":23,"title":24},8,"MySQL数据库字典导出功能",{"id":26,"title":27},10,"Python基础整理之if、while、for",[29],{"id":30,"name":21},27,4201,"https:\u002F\u002Ftp.myong.top\u002Fstorage\u002Farticle\u002F87\u002F675ea24d1392f61fb3cd682702835d.jpg",[34,39,44,49,54],{"id":35,"title":36,"create_time":37,"description":38},95,"Django启用memcache缓存","2020-10-23 11:17:27","在动态网站中,用户所有的请求,服务器都会去数据库中进行相应的增,删,查,改,渲染模板,执行业务逻辑,最后生成用户看到的页面.当一个网站的用户访问量很大的时候,每一次的的后台操作,都会消耗很多的服务端资源,所以必须使用缓存来减轻后端服务器的压力.",{"id":40,"title":41,"create_time":42,"description":43},91,"用Python实现编程语言 20 年的动态排行榜","2020-06-24 16:06:54","爬取一下，自2001年5月至今，TIOBE 编程语言排行榜上编程语言的变化情况，看一下在接近20年的时间里，编程语言的热度是如何变化的。\r\n",{"id":45,"title":46,"create_time":47,"description":48},100,"re正则表达式","2021-07-10 18:09:52","正则表达式是一个特殊的字符序列，它能帮助你方便的检查一个字符串是否与某种模式匹配，本文罗列re正则表达式中，常用的匹配符号。",{"id":50,"title":51,"create_time":52,"description":53},34,"Python基础整理之列表常见操作","2019-02-10 16:53:55","列表是最常用的Python数据类型，它可以作为一个方括号内的逗号分隔值出现。列表的数据项不需要具有相同的类型",{"id":55,"title":56,"create_time":57,"description":58},63,"Python与mysqldump的数据库备份","2019-10-14 15:35:33","mysqldump是备份MySQL数据库的一种好工具。它相对于用phpmyadmin等备份工具更加快速，又避免受php.ini等的限制，在windows系统下还可以结合计划任务实现定时远程备份数据库",1783431672734]