PHP Converting Integer to Date reverse of strtotime

Question

lt  php echo strtotime  2014-01-01 00 00 01     lt hr gt       output is 1388516401   gt    I am surprised if it can be reverse  I mean can I convert 1388516401 to 2014-01-01 00 00 01  What I actually want to know is  what s the logic behind this conversion  How php convert date to a specific integer

User · Answer

Can you try this   echo date  Y-m-d H i s   1388516401     As noted by theGame      This means that you pass in a string value for the time  and optionally a value for the current time  which is a UNIX timestamp  The value that is returned is an integer which is a UNIX timestamp    echo strtotime  2014-01-01 00 00 01      This will return into the value 1388516401  which is the UNIX timestamp for the date 2014-01-01  This can be confirmed using the date   function as like below   echo date  Y-m-d   1198148400      echos 2014-01-01

User · Answer

The time   function displays the seconds between now and the unix epoch   01 01 1970  00 00 00 GMT   The strtotime   transforms a normal date format into a time   format  So the representation of that date into seconds will be   1388516401    Source  http   www php net time

User · Answer

I guess you are asking why is 1388516401 equal to 2014-01-01      There is an historical reason for that  There is a 32-bit integer variable  called time t  that keeps the count of the time elapsed since 1970-01-01 00 00 00  Its value expresses time in seconds  This means that in 2014-01-01 00 00 01 time t will be equal to 1388516401   This leads us for sure to another interesting fact     In 2038-01-19 03 14 07 time t will reach 2147485547  the maximum value for a 32-bit number  Ever heard about John Titor and the Year 2038 problem   D

User · Answer

Yes you can convert it back  You can try   date  Y-m-d H i s   1388516401     The logic behind this conversion from date to an integer is explained in strtotime in PHP      The function expects to be given a string containing an English date format and will try to parse that format into a Unix timestamp  the number of seconds since January 1 1970 00 00 00 UTC   relative to the timestamp given in now  or the current time if now is not supplied    For example  strtotime  1970-01-01 00 00 00   gives you 0 and strtotime  1970-01-01 00 00 01   gives you 1   This means that if you are printing strtotime  2014-01-01 00 00 01    which will give you output 1388516401  so the date 2014-01-01 00 00 01 is 1 388 516 401 seconds after January 1 1970 00 00 00 UTC

[php] PHP Converting Integer to Date, reverse of strtotime

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