更少的& lt;如果我设置字符串PHP，操作符无法识别 - less < operator not recognize if I set like string PHP

我对PHP有奇怪的问题。当我将字符串设置为'<'并且如果我用几个字符串创建新字符串那么当转到'<'时它将停止工作并转到脚本的下一行

$a = new SomeObject();
$a->where('id', 13332, "<");
public function where($column, $param, $operator = '=') {
    echo strlen($operator);
    if (isset($column) && strlen($operator) > 0) {
        echo $operator;
        if ($operator === '>') {
            $this->_where = ' WHERE ' . $column . '>?';
        } else if ($operator == '<') {
            $this->_where = ' WHERE ' . $column . '<?';
        } else if ($operator === '=') {
            $this->_where = ' WHERE ' . $column . '=?';
        } else {
            $this->_where = ' WHERE ' . $column . $operator . '?';
        }
        $this->_where = ' WHERE ' . $column . chr(0x3c) . '?';
        echo '<br/>' . $this->_where . '<br/>';
    } else {
        throw new 'Exception('We need to have $column variable like string and $param like Param!', 500);
    }
    echo '<br/>c';
}

结果是:
1 & lt;WHERE id c

我的问题是为什么更少的<是不能得到像字符串。>和=操作符是OK的。但是<就是不被认可。我做错了什么?

删除一行，它将工作(您自己测试一个):-

<?php
error_reporting(E_ALL); //check all type of errors
ini_set('display_errors',1); // display those if any happen
$a = new SomeObject();
$a->where('id', 13332, "<");
public function where($column, $param, $operator = '=') {
    echo strlen($operator);
    if (isset($column) && strlen($operator) > 0) {
        echo $operator;
        if ($operator === '>') {
            $this->_where = ' WHERE ' . $column . '> ?'; // added space
        } else if ($operator == '<') {
            $this->_where = ' WHERE ' . $column . '< ?'; // added space
        } else if ($operator === '=') {
            $this->_where = ' WHERE ' . $column . '= ?'; // added space
        } else {
            $this->_where = ' WHERE ' . $column . $operator . '?';
        }
        //$this->_where = ' WHERE ' . $column . chr(0x3c) . '?';  remove this line
        echo '<br/>' . $this->_where . '<br/>';
    } else {
        throw new 'Exception('We need to have $column variable like string and $param like Param!', 500);
    }
    echo '<br/>c';
}

注意:-

不工作的原因:-

你必须添加空格也使其正确(评论@RiggsFolly)(为了浏览器显示的缘故)

你只是重写了你的条件。(由@JonStirling评论和示例:- https://3v4l.org/vCO5Z)(用于工作目的)

这一行:

$this->_where = ' WHERE ' . $column . chr(0x3e) . '?';

你覆盖了你以前的所有更改，所以难怪你不能看到正确的结果

请尝试这个函数，让我知道它是否会给你想要的输出

public function where($column, $param, $operator = '=') {
    echo strlen($operator);
    if (isset($column) && strlen($operator) > 0) {
        echo $operator;
        if ($operator === '>') {
            $this->_where = ' WHERE ' . $column . '> ?';
        } else if ($operator == '<') {
            $this->_where = ' WHERE ' . $column . '< ?';
        } else if ($operator === '=') {
            $this->_where = ' WHERE ' . $column . '= ?';
        } else {
            $this->_where = ' WHERE ' . $column . $operator . ' ?';
        }
        if($this->_where != '')
        {
            $this->_where .= ' and ' . $column . chr(0x3e) . ' ?';
        }
        else
        {
          $this->_where = ' WHERE ' . $column . chr(0x3e) . ' ?';
        }
        echo '<br/>' . $this->_where . '<br/>';
    } else {
        throw new 'Exception('We need to have $column variable like string and $param like Param!', 500);
    }
    echo '<br/>c';
}