php 读取 txt 文件的时候,第一行总是 不能正确识别数字,怎么办呢?

我逐行读取一个 txt 文件的内容,
但是每个文件第一行总是不能正确识别,
请问怎么做呢?

    $rTxt = fopen( $sTxt  ,"r" );
    
    while( $str = fgets($rTxt) )
    {
    
        $arr = explode( ',' , $str );
        Var_Dump( $arr[0] );
    }
    
    fclose( $rTxt );

txt 文件内容:

1393592460,10680,10660,10650,10720,6040,3.227103E+08,0,0,108,4746,0,0
1393592520,10656,10697,10656,10701,4888,2.612444E+08,0,0,203,6858,0,0
1393592580,10697,10672,10672,10700,1294,6.911194E+07,0,0,281,7086,0,0
1393592640,10671,10667,10661,10675,1706,9.101747E+07,0,0,354,7590,0,0
1393592700,10669,10650,10648,10670,2340,1.246486E+08,0,0,448,8664,0,0
1393592760,10652,10640,10632,10656,1938,1.031578E+08,0,0,545,9282,0,0
1393592820,10641,10657,10641,10662,1746,9.297165E+07,0,0,631,8922,0,0
......

每次读取的时候,文件第一行的第一个数字长度总是不对,应该有个看不见的字符串..:

string(13) "1393592460"
string(10) "1393592520"
string(10) "1393592580"
string(10) "1393592640"

回复内容：

我逐行读取一个 txt 文件的内容,
但是每个文件第一行总是不能正确识别,
请问怎么做呢?

    $rTxt = fopen( $sTxt  ,"r" );
    
    while( $str = fgets($rTxt) )
    {
    
        $arr = explode( ',' , $str );
        Var_Dump( $arr[0] );
    }
    
    fclose( $rTxt );

txt 文件内容:

1393592460,10680,10660,10650,10720,6040,3.227103E+08,0,0,108,4746,0,0
1393592520,10656,10697,10656,10701,4888,2.612444E+08,0,0,203,6858,0,0
1393592580,10697,10672,10672,10700,1294,6.911194E+07,0,0,281,7086,0,0
1393592640,10671,10667,10661,10675,1706,9.101747E+07,0,0,354,7590,0,0
1393592700,10669,10650,10648,10670,2340,1.246486E+08,0,0,448,8664,0,0
1393592760,10652,10640,10632,10656,1938,1.031578E+08,0,0,545,9282,0,0
1393592820,10641,10657,10641,10662,1746,9.297165E+07,0,0,631,8922,0,0
......

每次读取的时候,文件第一行的第一个数字长度总是不对,应该有个看不见的字符串..:

string(13) "1393592460"
string(10) "1393592520"
string(10) "1393592580"
string(10) "1393592640"

很有可能是utf8 bom字符。
引用 SO How to remove multiple UTF-8 BOM sequences

//Remove UTF8 Bom

function remove_utf8_bom($text)
{
    $bom = pack('H*','EFBBBF');
    $text = preg_replace("/^$bom/", '', $text);
    return $text;
}

用这个函数处理一下你的第一行应该就好了。

想知道更多关于BOM的知识：
知乎 - 「带 BOM 的 UTF-8」和「无 BOM 的 UTF-8」有什么区别
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