How to determine the data encoding of file_get_contents

How to determine file_get_contents to the data is what encoding, such as the question, EUC-CN is the most commonly used expression of GB2312. The "GB2312" on the browser encoding table usually refers to the "EUC-CN" notation. However, if you use mb_detect_encoding, you cannot get the correct result. how do you determine the encoding of the data in the list & quot; gb2312 file_get_contents?
Example

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EUC-CN is the most commonly used representation of GB 2312. The "GB2312" on the browser encoding table usually refers to the "EUC-CN" notation.

However, you cannot get the correct result by using mb_detect_encoding.
You can call the encoding location in the list "gb2312, gbk, UTF-8"
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Encoding determines content, content cannot determine encoding,
For example, to see a gbk Chinese character, can also be seen as two ISO-8859-1 characters
Therefore, mb_detect_encoding can only be guessed. since it is a guess, it cannot be completely correct (in fact, it is not absolutely correct)

For the content obtained by file_get_contents, if it is a web page, you can use meta to determine,
Without such information, you can only "guess"
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Discussion

Encoding determines content, content cannot determine encoding,
For example, to see a gbk Chinese character, can also be seen as two ISO-8859-1 characters
Therefore, mb_detect_encoding can only be guessed. since it is a guess, it cannot be completely correct (in fact, it is not absolutely correct)

For the content obtained by file_get_contents, if it is a web page, you can use meta to determine,
Without such information, you can only "guess"