/*************by garcon1986*********/
//print和echo的区别:
//1. echo可以输入多个字符串,而print不能。
print "hello"."world"; //成功
echo "hello"."world"; //成功
//print "hello","world"; //失败
echo "hello","world"; //成功
//2. echo比print更快。
$stime = microtime(true);
print "hello"."world";
$etime = microtime(true);
$total = $etime - $stime;
echo $total.'
';
//microtime — Return current Unix timestamp with microseconds
$stime2 = microtime(true);
echo "hello"."world";
$etime2 = microtime(true);
$total2 = $etime2 - $stime2;
echo $total2.'
';
//执行结果:
//helloworld0.0014331340789795
//helloworld0.00018310546875
//看到echo比print更快。
//print_r — Prints human-readable information about a variable 或数组
$a = "sajfd sfjal sfjalwureoi weu sj we fk io ";
print_r($a);
echo '
';
$a = array("b","c","d");
print_r($a);
echo '
';
//var_dump — Dumps information about a variable 或数组
//var_dump -- 打印变量的相关信息
$a = "sajfd sfjal sfjalwureoi weu sj we fk io ";
var_dump($a);
echo '
';
$a = array("b","c","d");
var_dump($a);
echo '
';
var_dump(array("b","c","d"));
echo '
';
?>
/************by garcon1986********/
//%% - 返回百分比符号
//%b - 二进制数
//%c - 依照 ASCII 值的字符
//%d - 带符号十进制数
//%e - 可续计数法(比如 1.5e+3)
//%f - 浮点数(local settings aware)
//%F - 浮点数(not local settings aware)
//%o - 八进制数
//%s - 字符串
//%u - 无符号十进制数
//%x - 十六进制数(小写字母)
//%X - 十六进制数(大写字母)
//printf()函数输出格式化的字符串
$str = "hello";
$number = 456;
//example1
printf("%s world. Day number %s", $str, $number); //输出: hello world. Day number 456
print "
";
//example2
printf("%%", $number); //%
print "
";
printf("%b", $number); //111001000
print "
";
printf("%c", $number); //ascii码
print "
";
printf("%d", $number); //456
print "
";
printf("%e", $number); //4.560000e+2
print "
";
printf("%f", $number); //456.000000
print "
";
printf("%F", $number); //456.000000
print "
";
printf("%o", $number); //710
print "
";
printf("%s", $number); //456
print "
";
printf("%u", $number); //456
print "
";
printf("%x", $number); //1c8
print "
";
printf("%X", $number); //1C8
print "
";
printf("With 2 decimals: %1\$.2f
With no decimals: %1\$u
",$number);
//With 2 decimals: 456.00
//With no decimals: 456
printf("With 2 decimals: %f
With no decimals: %1\$u
",$number);
//With 2 decimals: 456.000000
//With no decimals: 456
//fprintf() 函数把格式化的字符串写到指定的输出流(例如:文件或数据库)。
$file = fopen("text.txt","w");
echo fprintf($file, "fprintf 1: %s world. Day number %u", $str, $number).'
'; //38
echo fprintf($file, "fprintf 2: %f", $number).'
'; //21
echo fprintf($file,"fprintf 3: With 2 decimals: %1\$.2f\nWith no decimals: %1\$u",$number).'
'; //56
//vprintf()函数输出格式化的字符串。
//vprintf() 中的 arg 参数位于数组中。数组的元素会被插入主字符串的百分比 (%) 符号处。该函数是逐步执行的。在第一个 % 符号中,插入 arg1,在第二个 % 符号处,插入 arg2,依此类推。
vprintf("vprintf: %s world. Day number %u", array($str,$number)); //vprintf: hello world. Day number 456
echo '
';
//sprintf() 函数把格式化的字符串写写入一个变量中。
$txt = sprintf("sprintf: %s world. Day number %u",$str,$number);
echo $txt.'
'; //sprintf: hello world. Day number 456
//vfprintf() Operates as fprintf() but accepts an array of arguments, rather than a variable number of arguments.
echo vfprintf($file, "vfprintf: %s world! Day number %u", array($str, $number)).'
'; //37
//vsprintf() Operates as sprintf() but accepts an array of arguments, rather than a variable number of arguments.
$txt = vsprintf("vsprintf: %s world. Day number %u",array($str,$number));
echo $txt.'
'; //vsprintf: hello world. Day number 456
?>

What’s still popular is the ease of use, flexibility and a strong ecosystem. 1) Ease of use and simple syntax make it the first choice for beginners. 2) Closely integrated with web development, excellent interaction with HTTP requests and database. 3) The huge ecosystem provides a wealth of tools and libraries. 4) Active community and open source nature adapts them to new needs and technology trends.

PHP and Python are both high-level programming languages that are widely used in web development, data processing and automation tasks. 1.PHP is often used to build dynamic websites and content management systems, while Python is often used to build web frameworks and data science. 2.PHP uses echo to output content, Python uses print. 3. Both support object-oriented programming, but the syntax and keywords are different. 4. PHP supports weak type conversion, while Python is more stringent. 5. PHP performance optimization includes using OPcache and asynchronous programming, while Python uses cProfile and asynchronous programming.

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.

PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.

PHP remains important in the modernization process because it supports a large number of websites and applications and adapts to development needs through frameworks. 1.PHP7 improves performance and introduces new features. 2. Modern frameworks such as Laravel, Symfony and CodeIgniter simplify development and improve code quality. 3. Performance optimization and best practices further improve application efficiency.

PHPhassignificantlyimpactedwebdevelopmentandextendsbeyondit.1)ItpowersmajorplatformslikeWordPressandexcelsindatabaseinteractions.2)PHP'sadaptabilityallowsittoscaleforlargeapplicationsusingframeworkslikeLaravel.3)Beyondweb,PHPisusedincommand-linescrip

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values and handle functions that may return null values.


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