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输出出现未定义变量揭示:Notice: Undefined variable: str in

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2016-06-13 11:47:221302browse

输出出现未定义变量提示:Notice: Undefined variable: str in
function Call(){
    for($i=0;$i      {
       $str.= $i."
";
       }
    return $str;
}

echo Call();

输出进出现Notice: Undefined variable提示
------解决方案--------------------
Notice: Undefined variable
是说你使用了未经赋值的变量的值

在你的 $str.= $i."
"; 中首次进入时 $str 没有被赋过值,所以要报错

function Call(){<br />    $str = ''; //这句不能少<br />    for($i=0;$i<=10;$i++)<br />      {<br />       $str.= $i."<br>";<br />       }<br />    return $str;<br />}<br /><br />echo Call();

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