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This article mainly introduces how php deletes the data from 3 days ago, which has a certain reference value. Interested friends can refer to it. I hope you will gain a lot after reading this article. Let's take a look at it.

Php delete 3 days ago data method: 1, through "date ('Ymd',strtotime ('-3 days'));" get the date of three days ago; 2, through "unlink ($file_name);" delete the file of three days ago.

This article operating environment: Windows7 system, PHP7.1 version, Dell G3 computer

How does php delete data from 3 days ago?

PHP writes daily data to the same day's files, reads them the next day, and deletes files from three days ago.

With regard to this script, my idea is that the file name directly uses the date of the day, and then it is convenient to read the file and delete the file. Such as: 20190218.txt

About time processing: you can use the date () function to get the current time. If you want to display the date, you can add a parameter to it, and the parameter specifies the format of the time display, such as data ("Ymd"), which is the date format I use this time, and the output data is "20190218". Date ("Y-m-d") is "2019-02-18". If you also display the specific time, date ("Y-m-d H:i:s"), the result is "2019-02-18 10:51:26". You can use the strtotime () method to get the time before or after a few days. The purpose of this method is to parse the date and time of the English text into a Unix timestamp. Usage such as: date ("Ymd", strtotime ("- 1 day"); get yesterday's date. If you get the date from three days ago, you can change "- 1 day" to "- 3 days"; of course, you can also change day to mouth,week,hour,year, etc., with "-" indicating the previous days or hours, and "+" indicating the time of the next few days or hours. Because it is calculated by timestamp, it can only be calculated before 1970. Number of seconds since January 1 1970 00:00:00 GMT.

$date = date ("Ymd"); $file_name ='/ tmp/'.$date.'.txt'

The above code is the part that gets the current time and generates the file name, which is stored in the / tmp directory.

PHP write file: writing a file requires a piece of data to write a line, starting with file_put_contents (), which is used to write a string to the file. The syntax of this method is:

File_put_contents (string $filename, mixed $data [, int $flags = 0 [, resource $context]])

The meanings of the parameters are:

To avoid errors, json_encode is used to encode json strings before data is written. When you use the file_put_contents method to write data, you must add FILE_APPEND, but the data will follow directly, and reading one line of data will read the whole file as one line of data, instead of taking one. The solution is to add a newline character after each row of data. Later, a more convenient file processing method for PHP is found, and this method is no longer used.

$fp = fopen ($file_name,'a'); / / Open the file, generate the file handle, and create a new one if the file does not exist. Fwrite ($fp,json_encode ($log). "\ n"); / / write data fclose ($fp); / / close the file

PHP reads the file: the method used is fgets (), which reads one line of data at a time.

$date = date ('Ymd',strtotime ('-1 day')); / / get the date of the previous day $file_name ='/ tmp/'.$date.'.txt'; / / the file name of the previous day if (file_exists ($file_name)) {$fp = fopen ($file_name, "r"); while (! feof ($fp)) {$log = fgets ($fp); $log = json_decode ($log, true) . / / use the read data, remember to check null, and the last line is a newline character.} fclose ($fp);}

PHP delete file: use the unlink method. If it succeeds, it returns true. If it fails, it returns false.

$date = date ('Ymd',strtotime ('-3 days')); / / get the date of three days ago $file_name ='/ tmp/'.$date.'.txt'; / / the file name of three days ago if (file_exists ($file_name)) {unlink ($file_name) Thank you for reading this article carefully. I hope the article "how php deletes data from 3 days ago" shared by the editor will be helpful to you. At the same time, I also hope you will support us and pay attention to the industry information channel. More related knowledge is waiting for you to learn!

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