php版的求表达式的真值表-TrueValueTable，真值表逻辑表达式_PHP教程

php版的求表达式的真值表-TrueValueTable，真值表逻辑表达式

php error_reporting(E_ALL & ~E_NOTICE); $expression=$_GET['TrueTable']; //读取输入框数据 if(!empty($_GET['TrueTable'])){ $expression=strtoupper($expression); //将输入的小写字母，替代成大写字母 $expressionArr=str_split($expression); //将$expression转换成数组 foreach($expressionArr as $v){ //把字母放在 $varTotal数组中 if($v>='A' && $v){ $varTotal[]=$v; } } $varTotal = array_unique($varTotal); //去掉$varTotal数组中重复的字母 sort($varTotal); //$varTotal数组中字母正向排序 $varTotal1 = preg_replace("/([A-Z])/","$\1",$varTotal); //$varTotal1数组中字母变成变量 $maxN = count($varTotal); //$expressionArr = preg_replace("/([A-Z])/","$\1",$expressionArr); //$expressionArr数组中字母变成变量 $newExpression=implode('',$expressionArr); //$expressionArr数组变成字符串 //echo $newExpression."
"; $newExpression= preg_replace("/([A-Z])->([A-Z])/","!\1|\2",$newExpression); $newExpression= preg_replace("/((.*?))->([A-Z])/","!\1|\2",$newExpression); $newExpression= preg_replace("/((.*?))->(.*?)/","!\1|\2",$newExpression); $newExpression= preg_replace("/([A-Z])->(.*?)/","!\1|\2",$newExpression); $expressionArr=str_split($newExpression); //将$expression转换成数组 $expressionArr = preg_replace("/([A-Z])/","$\1",$expressionArr); $newExpression=implode('',$expressionArr); //echo $newExpression; } ?>

[ 说明：析取(|) , 合取(&) , 非(!) , 蕴含(->) , 等价(=) ]