php 基础笔记
/***************************bygarcon1986********************************/<?php//if 语句$a = $b = 3;if($a = $b)print "a is equal to b<br>";//else 语句if($a < $b){print "a is smaller than b";} else {print "a is not smaller than b<br>";}//elseif = else if 语句if($a>$b){print "a is bigger than b";}else if($a = $b){print "a is equal than b";}else {print "a is smaller to b<br>";}// when you don't use "{}", you can't separate elseif.//当不用{}时，elseif不能分开if($a>$b):print "a>b";elseif($a==$b)://else if($a==$b): // this is wrongprint "a=b";print '<br>';endif;//while语句$i = 0;while($i<=10){print $i++.'<br>';}$i=15;while($i<=20):print$i;$i++;endwhile;print '<br>';//The difference between 'do while' and 'while' is: 'do while' will execute once at least.//do while 和while的区别在于前者至少要执行一次$i=0;do {echo $i;}while($i>0);echo '<p>';//do while example 2do {if ($i < 5) {echo "i is not big enough";break;}$i *= 2;if ($i < 50) {break;}echo "i is ok";/* process i */} while (0);//for(expression1; expression2; expression3) statement语句//example1for($i=0;$i<=6;$i++){print $i;}echo '<br>';//example2for($i=0; ; $i++){if($i>10){break;}print $i;}echo '<br>';//example3for($i=0;;){print $i;$i++; if($i>6){break;}}echo '<br>';//example4$i=0;for(;;){if($i>6){break;}print $i;$i++;}echo '<br>';//example5for($i=0;$i<=10;print $i, $i++);echo '<p>';//foreach语句//example1$arr = array('s','j','g','w','l');foreach($arr as $value){echo "$value<br>"; //$value is user-defined.}unset($value);//list to replace foreach, same result//使用list代替foreach，结果是一样的$arr=array('s','j','g','w','l');reset($arr);while(list(,$value)= each($arr)){echo "value: $value <br>/n";}//example2//foreach version$arr = array('i','n','i','a','o','w');foreach($arr as $key => $value){echo "key:$key, value:$value<br>/n";}// list($key,$value)$arr = array('w','o','a','i','n','i');//reset($arr);while(list($key,$value)=each($arr)){echo "key:$key, value:$value<br>/n";}//foreach new examples//一维数组不含key$a = array(1,2,3,4,5);foreach($a as $v){echo "current line of /$a is: $v<br>";}//一维数组含key$i=5;foreach($a as $k => $v1){echo "/$a[$i] : $k => $v1 <br>/n";$i++;}//一维数组key,指定$a = array("sjg"=>123,"ai"=>456,"wl"=>7890);foreach($a as $ke=>$va){echo "$ke, $va<br>";echo "/$a[$ke]=>$va<br>";}//multiple-arrays多维数组$s = $w = 0;$a = array("sjg"=>array("work"=>"hard", "sleep"=>"well","business"=>"good"),"ai"=>array("lo"=>"ve","ve"=>"ry", "mu"=>"ch"),"wl"=>array("study"=>"hard", "rest"=>"pasmal","exam"=>"passed"));foreach($a as $key=>$value1){foreach($value1 as $key2=>$value2){echo "$key, $key2, $value2<br>/n";}//echo "$a, $value1";}/*$x2 = array("早上"=>array("8点"=>"起床","8点半"=>"到单位","中午前"=>"工作"),"下午"=>array("12点到1点"=>"吃饭休息","1点到6点"=>"继续工作"),"晚上"=>array("6点到7点"=>"吃好晚餐","7点到10点"=>"自由活动"));//输出我早上中午前在干什么echo $x2["早上"]["中午前"];*///$a = array();$a = "a";$a = "b";$a = "y";$a = "z";//二维数组foreach ($a as $key1=> $v1) {foreach ($v1 as $key2=>$v2) {echo "$key1,$key2,$v2.<br>/n";}}//break//eaxmple1$arr = array("one", "two","three",4,'5');while(list(,$var)=each($arr)){if($var==4){break;}echo "$var<br>/n";}//example2$i = 0;while(++$i){switch($i){case 4:echo "line 4<br>/n";break 1;case 8:echo "line 8<br>/n";break 2;default:break;}}//continue//example1while (list ($key, $value) = each($arr)) {if (!($key % 2)) { // skip odd memberscontinue;}do_something_odd($value);}$i = 0;while ($i++ < 5) {echo "Outer<br />/n";while (1) {echo "Middle<br />/n";while (1) {echo "Inner<br />/n";continue 3;}echo "This never gets output.<br />/n";}echo "Neither does this.<br />/n";}//example2for($i=0; $i<5; ++$i){if($i==2)continue ;print "$i/n";}//switch//example1:对比elseif 和 switchif($i == 0){echo "i equals 0";}elseif($i==1){echo "i equals 1";}switch($i){case 0:echo "i equals 0";break;case 1:echo "i equals 1";break;}//example2switch($i){case "apple":echo "i is apple";break;case "banana":echo "i is banana";break;default:echo "i is not a fruit.";}//example3switch($i):case 0:echo "i equals 0";case 1:echo "i equals 1";default:echo "i is not equals 0 or 1";endswitch;//require() 语句包含并运行指定文件。require "";require $somefile;require ('somefile.txt');//include 语句包含并运行指定文件。//这两种结构除了在如何处理失败之外完全一样。include() 产生一个警告而 require() 则导致一个致命错误。//换句话说，如果想在遇到丢失文件时停止处理页面就用 require()。//require_once同一个文件只包含一次，不区分大小写。//include_once同一个文件只包含一次，不区分大小写。?>
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