[{"data":1,"prerenderedAt":60},["ShallowReactive",2],{"article-10":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":14,"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":32,"comments":14,"cover":33,"relevant":34},10,"Python基础整理之if、while、for","python,循环,python基础","学习python已经有一段时间了，近期有时间就整理整理学过的东西，温故而知新。",5,"一、if-else\n\n代码格式\n\n```python\nif 条件:\n    满足条件时\nelse:\n    不满足条件时\n```\n栗子：\n\n```python\nchePiao = 1 # 用1代表有车票，0代表没有车票\nif chePiao == 1:\n    print(\"有车票，可以上火车\")\n    print(\"终于可以见到Ta了，美滋滋~~~\")\nelse:\n    print(\"没有车票，不能上车\")\n    print(\"亲爱的，那就下次见了，一票难求啊\")\n```\n运行结果\n\n```python\n有车票，可以上火车\n终于可以见到Ta了，美滋滋~~~\n```\n二、elif\n\n代码格式：\n\n```python\nif 满足1:\n    事情1\nelif 满足2:\n    事情2\nelif 满足3:\n    事情3\n```\n案例：\n\n```python\nscore = 77\nif score>=90 and score\u003C=100:\n    print('本次考试，等级为A')\nelif score>=80 and score\u003C90:\n    print('本次考试，等级为B')\nelif score>=70 and score\u003C80:\n    print('本次考试，等级为C')\nelif score>=60 and score\u003C70:\n    print('本次考试，等级为D')\nelif score>=0 and score\u003C60:\n    print('本次考试，等级为E')\n```\n运行结果\n\n```python\n本次考试，等级为C\n```\n和else一起使用\n\n格式：\n\n```python\nif 满足1:\n    事情1\nelif 满足2:\n    事情2\nelse\n    其他事情\n```\n三、if嵌套\n\n格式：\n\n```python\nif 条件1：\n    满足条件1。。。。\n    if 条件2:\n        满足条件2。。。\n```\n案例：\n\n```python\nchePiao = 1     # 用1代表有车票，0代表没有车票\ndaoLenght = 9     # 刀子的长度，单位为cm\nif chePiao == 1:\n    print(\"有车票，可以进站\")\n    if daoLenght \u003C 10:\n        print(\"通过安检\")\n    else:\n        print(\"没有通过安检\")\n        print(\"刀子的长度超过规定，等待警察处理...\")\nelse:\n    print(\"没有车票，不能进站\")\n```\n运行结果\n\n```python\n有车票，可以进站\n通过安检\n```\n情节描述：上公交车，并且可以有座位坐下\n\n要求：输入公交卡当前的余额，只要超过2元，就可以上公交车；如果空座位的数量大于0，就可以坐下\n\n代码：\n\n```python\nmoney = 10\nseatCount = 0\nif money > 2: \n    print(\"可以上车\") \n    if(seatCount > 0): \n        print(\"可以坐下\") \n    else: \n        print(\"不可以坐下\")\nelse: \n    print(\"不可以上车\") \n```\n运行结果\n\n```python\n可以上车\n不可以坐下\n```\n四、while循环\n\n格式：\n\n```python\nwhile 条件:\n    满足条件。。。。\n```\n案例:\n\n```python\ni =0\nwhile i \u003C 3:\n    print(\"当前是第%d次执行循环\"%(i+1))\n    print(\"i=%d\"%i)\n    i+=1\n```\n运行结果：\n\n```python\n当前是第1次执行循环\ni=0\n当前是第2次执行循环\ni=1\n当前是第3次执行循环\ni=2\n```\n五、while循环的应用\n\n1、计算1-100的累加和\n\n```python\ni = 1\nsum = 0\nwhile i \u003C= 100:\n    sum = sum + i\n    i += 1\nprint('1~100的累加和为：%d'%sum)\n```\n运行结果：\n\n\n1-100的累加和为：5050\n\n2、计算1~100之间偶数的累加和\n\n```python\ni = 1\nsum = 0\nwhile i \u003C= 100:\n    if i % 2 == 0:\n        sum = sum + i\n    i += 1\nprint('1-100的偶数累加和：%d'%sum)\n```\n运行结果：\n\n```python\n1-100的偶数累加和：2550\n```\n六、while循环的嵌套\n\n格式：\n\n```python\nwhile 条件1:\n    满足条件1。。。。\n    while 条件2：\n        满足条件2。。。\n```\n案例一：打印如下图形\n```python\n\n*\n* *\n* * *\n* * * *\n* * * * *\n```\n代码块：\n\n```python\ni = 1\nwhile i \u003C= 5:\n    j = 1\n    while j \u003C= i:\n        print('* ', end= '')\n        j += 1\n    print('\\n')\n    i += 1\n```\n案例二：九九乘法表\n\n```python\ni = 1\nwhile i \u003C= 9:\n    j = 1\n    while j \u003C= i:\n        print('%d*%d=%-4d'%(j, i, i * j), end='')\n        j += 1\n    print('\\n')\n    i += 1\n```\n运行结果：\n\n```python\n1*1=1\n\n1*2=2   2*2=4\n\n1*3=3   2*3=6   3*3=9\n\n1*4=4   2*4=8   3*4=12  4*4=16\n\n1*5=5   2*5=10  3*5=15  4*5=20  5*5=25\n\n1*6=6   2*6=12  3*6=18  4*6=24  5*6=30  6*6=36\n\n1*7=7   2*7=14  3*7=21  4*7=28  5*7=35  6*7=42  7*7=49\n\n1*8=8   2*8=16  3*8=24  4*8=32  5*8=40  6*8=48  7*8=56  8*8=64\n\n1*9=9   2*9=18  3*9=27  4*9=36  5*9=45  6*9=54  7*9=63  8*9=72  9*9=81\n```\n七、for循环\n\n格式：\n\n```python\nfor 临时变量 in 列表或者字符串等：\n    循环满足条件。。。\nelse\n    不满足条件执行\n```\n案例一\n\n```python\nstr = 'hello word'\nfor i in str:\n    print(i)\n```\n结果：\n\n```python\nh\ne\nl\nl\no\n\nw\no\nr\nd\n```\n八、break和continue\n```python\n1、break\n```\nfor循环带入break\n\n案例\n\n```python\nname = 'dongGe'   \nfor x in name:\n    print('----')\n    if x == 'g':\n        break\n    print(x)\n```\n运行结果：\n\n```python\n----\nd\n----\no\n----\nn\n----\n```\nwhile循环带入break\n\n案例\n\n```python\ni = 0\nwhile i \u003C 10:\n    i = i + 1\n    print('----')\n    if i == 5:\n        break\n    print(i)\n```\n运行结果\n\n```python\n----\n1\n----\n2\n----\n3\n----\n4\n----\n```\n小结 break的作用：用来结束整个循环\n\n2、continue\n\nfor循环带入continue\n\n实例\n\n```python\nname = 'dongGe'\nfor x in name:\n    print('----')\n    if x == 'g':\n        continue\n    print(x)\n\n```\n运行结果：\n\n```python\n----\nd\n----\no\n----\nn\n----\n----\nG\n----\ne\n```\nwhile循环带入continue\n\n实例\n\n```python\ni = 0\nwhile i\u003C10:\n    i = i+1\n    print('----')\n    if i==5:\n        continue\n    print(i)    \n```\n运行结果：\n\n```python\n----\n1\n----\n2\n----\n3\n----\n4\n----\n----\n6\n----\n7\n----\n8\n----\n9\n----\n10\n```\n小结：continue的作用：用来结束本次循环，紧接着执行下一次的循环",null,0,531,"",1,"2019-01-17 22:17:54","2026-04-19 10:49:30",128,"Python",{"id":23,"title":24},9,"Python整理之字符串操作",{"id":26,"title":27},11,"《MongoDB权威指南》之MongoDB初探",[29],{"id":30,"name":21},27,1955,4,"https:\u002F\u002Ftp.myong.top\u002Fstorage\u002Farticle\u002F87\u002F675ea24d1392f61fb3cd682702835d.jpg",[35,40,45,50,55],{"id":36,"title":37,"create_time":38,"description":39},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":41,"title":42,"create_time":43,"description":44},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":46,"title":47,"create_time":48,"description":49},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":51,"title":52,"create_time":53,"description":54},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":56,"title":57,"create_time":58,"description":59},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",1783431672729]