如何一步步匹配(how to match step by step)

 我有一个字符串变量，通过连接变得更大。 我需要验证每个子字符串（每个循环迭代）。 
 
 我创建了一个模式来匹配字符串的最终有效形式。 
 
 如何验证字符串的每个子字符串（部分但顺序正确）？ 
 
    $pattern = "#\{/?MYTAG(\d*)?\}#i" 
    $myString = ''

    while (true) {
     $myString .= $aChar;

      // {    => valid
      // {m   => valid
      // {my  => valid
      // {myz => invalid break the loop

      if ( preg_match($pattern, $myString) ) {

       }
    }
 
 我试过用? 修改以使字符可选。 但它匹配部分字符串： 
 
// {mysdf
// it matches {my
// I want to return false, not get the valid part of the string
 
 我希望这是有道理的。 

I have a string variable that gets bigger by concatenation. I need to validate every substring (every loop iteration).
 
I created a pattern to match the final valid form of the string.
 
How can I validate every substring (partial but in correct order) of the string ?
 
    $pattern = "#\{/?MYTAG(\d*)?\}#i" 
    $myString = ''

    while (true) {
     $myString .= $aChar;

      // {    => valid
      // {m   => valid
      // {my  => valid
      // {myz => invalid break the loop

      if ( preg_match($pattern, $myString) ) {

       }
    }
 
I tried to use the ? modified to make the character optional. But then it matches the partial string:
 
// {mysdf
// it matches {my
// I want to return false, not get the valid part of the string
 
I hope this makes sense.

原文：https://stackoverflow.com/questions/38400521