Summary of articles about conversion introduction-PHP Tutorial-php.cn

Summary of articles about conversion introduction

伊谢尔伦

Release： 2023-03-10 09:22:01

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Problem In javascript, both integers and floating-point numbers belong to the Number data type (one of the simple data types). We often find that when printing a floating-point number such as 1.0, the result is 1 instead of 1.0. This is due to saving the floating-point number. Points take up twice as much memory as storing integer values, so ECMAScript wastes no time converting floating point numbers to integers. Although the above situation makes patients with obsessive-compulsive disorder a little uncomfortable, it is not a big mistake anyway. The next situation will be very scary. For example, when we calculate 0.1 plus 0.2, the output result is not 0.3, but 0.3000000000000004. what the fuck? ! For children who encounter this situation for the first time, do you feel that your world view has been challenged? The reason was so I quickly opened the book to save my soul and body, and found that it was clearly written in the book: ECMAScrip is based on IEEE754 numerical floating point calculation. If you don’t know what IEEE754 is, click here. This numerical calculation method will save the value as Binary is then calculated. Since floating point numbers are infinite when expressed in binary, they will be

1. Detailed introduction to PHP knowledge points

Summary of articles about conversion introduction

Introduction: The problem is that in javascript both integers and floating point numbers belong to the Number data type (one of the simple data types), we It is often found that when printing a floating point number such as 1.0, the result is 1 instead of 1.0. This is because the memory space for storing floating point numbers is twice that of storing integer values, so ECMAScript will lose no time in converting floating point numbers to integers. Although the above situation makes patients with obsessive-compulsive disorder a little uncomfortable, it is not a big mistake anyway. The next situation will be very scary. For example, when we calculate 0.1 plus 0.2, its output result...

Summary of articles about conversion introduction

Introduction: Post a code written when doing data cleaning. When doing data processing, the original file data needs to be converted into a certain format during processing. , Original file data: 123.txt1,3,42,3,51,2,3,52,5 converted into a two-dimensional list using Python: #!/usr/bin/env python#coding=utf-8def ;loadDataSet(): &n...

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Summary of articles about conversion introduction

4. BBS design summary based on mysql

Summary of articles about conversion introduction

Introduction: 6. bbsd and cq66 server side transformation Change, which function to call. The consistency of concurrent operations is guaranteed by the locking function of the database. MySQL should support this kind of lock. The article may be more troublesome, but it also converts the original file operations into the BoardManage class that operates the database...

5. About the thick detailed introduction

Summary of articles about conversion introduction

简介：concat()把元素衔接到数组中join()将数组的所有元素转换为字符串，并衔接起来splice()插入、删除、替换数组元素push()把元素添加到数组尾部pop()移除数组最后一个元素shift()移除数组的第一个元素unshift()在数组头部插入元素slice()返回数组的一部分every()测试断言函数是否对每个数组元素都为真some()测试是否至少有一个数组元素能让断言函数为真fore...

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Summary of articles about conversion introduction

简介： /// <summary> /// 提供方法将其他类型转换为Json /// </summary> public st

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Summary of articles about conversion introduction

简介： python中的struct主要是用来处理C结构数据的，读入时先转换为Python的字符串类型，然后再转换为Python的结构化类型，比如元组(tuple)啥的~。一般输入的渠道来源于文件或者网络的二进制流。1.struct.pack()和struct.unpack() 在转化过程中，主要用到了一个格式化字符串(format...

8. 有关格式要求的文章推荐10篇

Summary of articles about conversion introduction

简介：PHP 自带函数 fputcsv 可以实现打印报表（Excel）功能。如果你的对报表格式要求不是很高，那么 fputcsv 是很好的选择。它执行效率高，不需要第三方库，用起来很方便。以上代码会在本地生成一个 csv 的文件，能够用 Excel 打开，是不是很简单呢。如果有中文，在 Linux 执行后，下载到本地打开会乱码，那么可以用 iconv 函数进行转换。$list = array();$tm...

9. 关于目录方法的详细介绍

Summary of articles about conversion introduction

简介：　　Python编程中常用的12种基础知识总结：正则表达式替换，遍历目录方法，列表按列排序、去重，字典排序，字典、列表、字符串互转，时间对象操作，命令行参数解析(getopt)，print 格式化输出，进制转换，Python调用系统命令或者脚本，Python 读写文件。　　1、正则表达式替换　　目标: 将字符串line中的 overview.gif 替换成其他字符串>>&g...

10. 关于-GBK的10篇文章推荐

Summary of articles about conversion introduction

简介：如何把数据从GB2312转换成UTF-8我使用了iconv和mb_convert_encoding两个函数都试了，然后发现结果是一样的，都会出现各种问题，不是哪里少字了就是直接错误，请问大神怎么解决啊------解决方案--------------------gbk 的数据插入到 utf8 的表，只需在插入前执行一次 mysql_query('set&nbs...

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