PHP reads files: implements data import and parsing

PHP reading files: implementing data import and parsing

Overview:
In PHP development, it is often necessary to read data from external files and perform data processing Import or parse. This article will introduce how to use PHP to read files, and provide some practical code examples to help developers quickly implement data import and parsing functions.

1. File reading

PHP provides a variety of functions for reading files, the commonly used ones are file_get_contents(), fread() and fgets().

1. file_get_contents() function:

Use the file_get_contents() function to read the entire file into memory as a string, suitable for small file reading operations .

The sample code is as follows:

$file = 'example.txt';
$data = file_get_contents($file);
echo $data;

The above code will read the data of the example.txt file and print it out.

2. fread() function:

Use the fread() function to read data of a specified length.

The sample code is as follows:

$file = 'example.txt';
$handle = fopen($file, 'r');
$data = fread($ handle, filesize($file));
echo $data;
fclose($handle);

The above code will use the fread() function to read the data of the example.txt file and its printed out. It should be noted that after reading the data, you need to call the fclose() function to close the file handle.

3. fgets() function:

Use the fgets() function to read file data line by line, which is suitable for reading large files.

The sample code is as follows:

$file = 'example.txt';
$handle = fopen($file, 'r');
while (!feof($ handle)) {

$line = fgets($handle);
echo $line;

}
fclose($handle);

The above code will use the fgets() function to read the data of the example.txt file line by line and add each line The data is printed line by line.

2. Data import

In actual development, it is often necessary to import data in files into a database or other storage media. The following takes importing data from a CSV file into the database as an example to illustrate how to implement data import.

The sample code is as follows:

$file = 'example.csv';
$handle = fopen($file, 'r');
$headers = fgetcsv($ handle); // Read the header of the CSV file
while (($data = fgetcsv($handle)) !== false) {

// 将每行数据导入到数据库
// ...

}
fclose($handle);

The above code will use the fgetcsv() function to read the data of the CSV file and import each line of data into the database line by line. Developers only need to add the corresponding logic for inserting into the database in the while loop.

3. Data Analysis

Sometimes, the data in the file is not stored in a fixed format and needs to be parsed before it can be used. The following takes data parsing of JSON files as an example to illustrate the implementation method of data parsing.

The sample code is as follows:

$file = 'example.json';
$data = file_get_contents($file);
$decoded_data = json_decode($data, true) ;
if ($decoded_data !== null) {

// 解析成功
// ...

} else {

// 解析失败
// ...

}

The above code will use the file_get_contents() function to read the JSON file data, and use the json_decode() function to parse the data. If the parsing is successful, you can continue to process the parsed data; if the parsing fails, you need to handle the parsing failure.

Conclusion:
This article introduces the common functions of PHP to read files and the implementation methods of data import and parsing, and provides corresponding code examples. We hope it can help developers quickly implement data import and parsing functions in actual projects.

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