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<div class="codetitle"><a style="CURSOR: pointer" data="73798" class="copybut" id="copybut73798" onclick="doCopy('code73798')"> 代码如下:<div class="codebody" id="code73798">
<?php
/****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 '
';
$a = array("b","d");
var_dump($a);
echo '
';
var_dump(array("b","d"));
echo '
';
?>
<?php
/****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",$number).'
'; //38
echo fprintf($file,"fprintf 2: %f",$number).'
'; //21
echo fprintf($file,"fprintf 3: With 2 decimals: %1$.2fnWith no decimals: %1$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。
$txt = sprintf("sprintf: %s world. Day number %u",$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",$number)).'
'; //37
//vsprintf() Operates as sprintf() but accepts an array of arguments,rather than a variable number of arguments.
$txt = vsprintf("vsprintf: %s world. Day number %u",$number));
echo $txt.'
'; //vsprintf: hello world. Day number 456
?>
（编辑：李大同）
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