How to tell if a file is a. csv file from the contents of a file

How to tell if a file is a. csv file from the contents of a file
The expansion name is not allowed in this area. Afraid of others to change the name of expansion
And I installed inside whether to include a comma, because some files are read out of the content is garbled? The result is that it will read garbled characters into commas?
And I need to judge the rigorous methods and theories of the. csv file, not for granted. In fact, only by the comma is not rigorous ah, in fact, garbled may become a comma, its 21 files have a comma is a qualified CSV file

Thank you, Master.

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No way
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Try Str_getcsv Analysis
http://php.net/manual/en/function.str-getcsv.php
Use error to determine
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No cases are garbled by reading commas

The CSV file is a text file, and the only thing that can be recognized is that each row has an equal number of column separators (the default is a comma)
Consider a qualified CSV file when the number of column separators that detect more than 80% rows is equal, given that there may be commas in the content (the content needs to be enclosed in quotation marks)

In addition, non-standard CSV, which is the content of the character type, is not enclosed in double quotation marks. At least php5.3 for win is not available
The Fgetcsv or Str_getcsv function reads correctly
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The CSV file expresses an array
If each row has a different number of columns, it is not a CSV
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Full Name

Comma separated Values
Edit this paragraph
Rules

1 The opening is not left empty to the behavior unit.
2 can contain or do not contain column name, including column name in the first line of the file.
31 rows of data do not collapse, no blank line.
4 A comma (that is,) is used as a delimiter, the column is empty also to express its existence.
5 column Contents If there are half-width commas (that is,) enclose the field value with a half-width quotation mark (that is, "").
6 column Contents If there is a half-width quotation mark (that is, "), you should replace it with a half-width double quotation mark (" ") and enclose the field value with a half-width quotation mark (" ").
7 file read-write quotation marks, comma operation rules are mutually inverse.
8 Internal code format is not limited, can be ASCII, Unicode or other.
9 special characters are not supported
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According to the requirements of the rules
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What format do you want the user's CSV to be? In addition, for the file, there is no garbled concept, only the concept of byte,
Garbled only a few bytes can not be displayed in the specified character set (such as GB2312).
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Use a comma (that is,) as a delimiter, and the column is empty to express its existence
This is important.
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Find a CSV to lead to other formats class can be successful is not, it is not, this curve to the salvation of the bar
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Explore

Reference:
Use a comma (that is,) as a delimiter, and the column is empty to express its existence
This is important.

I told you, did you say that?
If you have a word inside of a comma, you read the content, do you know whether the comma is a delimiter or a valid character?


You can follow a comma to read a. csv file

But you only have to use commas to make a difference. CSV file this is too farfetched. The reason is too inadequate

This comma is not a sufficient condition

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