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Personally record some of your daily life When writing PHP code, some minor problems encountered will be updated from time to time;
Welcome everyone to point out the errors in the problem in time. You can mark the specific problem number when making comments. Thank you everyone and share your encouragement;
1, float data type output format problem
$float1 = 1.123;$float2 = 2.3e3;$float3 = 8E-5;var_dump($float1, $float2, $float3); //float(1.123) float(2300) float(8.0E-5)var_dump(number_format(8E-5, 5)); //string(7) "0.00008"
You will find that 8E-5 is not output as 0.00008. This is because PHP will automatically convert some numbers with too many digits into Scientific notation displays
. At this time, if you want to output the format as 0.00008, you can use number_format(). Also note that this function returns string
2. After using the . splicing character, it is automatically converted to string type
$a = 12;$b = 1.3;$c = true; //转为1var_dump($a . $b . $c); //string(6) "121.31"
3, strlen(), strpos() Chinese character processing
strlen() returns the length of the string, in bytes, one for English and three for Chinese;
English is easy to say, no special processing is needed, while Chinese can use the special mb_strlen()
echo strlen('string'); //6echo strlen('你好！世界'); //15（5个中文字符*3）echo strlen('你好！PHP'); //12（三个中文字符*3 + 3个英文）echo mb_strlen('你好！世界'); //5echo mb_strlen('你好！PHP'); //6 每个都按字符算
strpos() is used to find whether a certain character appears in a specified string. If a match is found in the string, the function will return the first matching character position. If no match is found, returns FALSE.
It should be noted that: the first position of the string is 0, not 1;
Similarly, this function also has problems in Chinese and English, and it also requires a special mb_strpos() function to handle it
echo strpos("hello php", "php"); //6echo strpos("hello php","he"); //0echo strpos("你好，php", "p"); //9echo mb_strpos("你好，php", "p"); //3
If you want to learn more about programming, please pay attention to the php training column!
The above is the detailed content of Recorded PHP daily attention points (1). For more information, please follow other related articles on the PHP Chinese website!
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mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),
SublimeText3 English version
Recommended: Win version, supports code prompts!
SublimeText3 Chinese version
Chinese version, very easy to use
Dreamweaver Mac version
Visual web development tools
VSCode Windows 64-bit Download
A free and powerful IDE editor launched by Microsoft
