如何将<< with > =和>替换为<=，并用<替换为<= with >和> =如果它们在同一个字符串中出现多次？

Question

我正在使用PHP工作。我有一个这样的字符串： “AND day_1> = day_2和day_1 < day_3” ，我想，以取代第一> =与<，我想替换第二<与> =

换句话说，我想扭转日期范围逻辑：

“AND day_1> = day_2和day_1 < day_3”

我想逆转这个样子：

“AND day_1 < day_2和day_1> = day_3 “

这里是我的代码：

$str = "AND day_1 >= day_2 AND day_1 < day_3"; 
echo "{$str}<br>"; 
$old_replace = array(">=", "<=", "<", ">"); 
$new_replace = array("<", ">", ">=", "<="); 
$count = 1; 
$str = str_replace($old_replace, $new_replace, $str, $count); 
echo $str; 

当我尝试使用字符串替换它这样做：

之前更换：AND day_1> = day_2和day_1 < day_3 后替换：AND day_1 < = = day_2和day_1 < == day_3

Answer 1

试试这个：

$replacements = Array("<="=>">",">="=>"<","<"=>">=",">"=>"<="); 
$str = strtr($str,$replacements);