I have a script which is fed dates in numerous different formats.
I want to save these dates as timestamps so they can easily be manipulated/ordered.
When i try an convert a mm-dd-yyyy type date to a timestamp, it fails.
When the script runs, it does not know what format it will be fed, and as such this cannot be specified. Near all other formats of date seem to be converted fine.
Could anyone advise how to fix this, or alternatively an alternative way that all date formats can be converted to an orderable, consistent format that can be manipulated?
Many Thanks
It sees strings with - in them as dd-mm-yyyy and / as mm/dd/yyyy.
See also this question and the comments on the documentation.
Possible solutions / workarounds:
on php 5.3, use date_create_from_format
on older php and not on windows, use strptime
if neither can be used, either replace the - to / when necessary, or use one of the regexes suggested you can find through the linked question.
Note however that at some time you do need to know what the format is to start with. Computers are not mindreaders. They can't, and never will be able to, distinguish between mm-dd-yyyy and dd-mm-yyyy in the overlap ranges (both mm and dd <= 12) if you don't provide the distinction.
Related
This question already has answers here:
Convert one date format into another in PHP
(17 answers)
Closed 15 days ago.
MediaWiki (the free software behind Wikipedia) stores database timestamps in a unique binary(14) format for fields of the database. This is described further in their timestamp documentation.
The format of timestamps used in MediaWiki URLs and in some of the
MediaWiki database fields is yyyymmddhhmmss. For example, the
timestamp for 2023-01-20 17:12:22 (UTC) is 20230120171222. The
timezone for these timestamps is UTC.
I have also seen a similar timestamp format in other places such as URLs for the Internet Archive. I am regularly needing to compare these timestamps against timestamps which are stored in a standard Unix timestamp format (seconds from the Unix epoch). I believe this should be a common format so it surprises me that I can't find a ready-made solution to easily convert from the MediaWiki format to a Unix timestamp.
What I'm most interested in is the best way to do this conversion. That is:
Relatively short/simple to understand code.
Most efficient algorithm.
Does detect errors in original format.
There is apparently a function that MediaWiki includes for conversion named "wfTimestamp" however I haven't been able to locate this function itself or the source code online and I understand it has a large number of unnecessary features beyond the simple conversion. One potential solution may be to remove other parts of that function, but I still don't know if that function is the optimal solution or if there's a better way. There are lots of questions on the more general conversion to timestamps but I'm hoping for something specific to this format. I've thought of a lot of ways to solve it such as a regular expression, mktime after string split, strtotime, etc... but I'm not sure which will be fastest for this particular task/time format if it had to be done a lot of times. I am assuming since this format exists in at least two places, an optimal solution for this specific format conversion could be useful for others as well. Thanks.
I think this is what you're probably looking:
$timestamp = strtotime("20230120171222");
// 1674234742
The Unix timestamp that this function returns does not contain information about time zones. In order to do calculations with date/time information, you should use the more capable DateTimeImmutable.
Please see here: https://www.php.net/manual/en/function.strtotime.php
You can use DateTime::createFromFormat function with specified format.
$date = DateTime::createFromFormat("YmdHis", "20230120171222", new \DateTimeZone('UTC'));
$timestamp = $date->getTimestamp();
I'm not sure that you can find more optimised way, because even if you will parse this manually, you have to consider that there are leap years and not every day has exactly 24 hours. PHP does it for you.
In order to interpret the string "20230120171222" as UTC time, the time zone must be specified with strtotime or the default time zone must be set to UTC.
$dateStr = "20230120171222";
$timestamp = strtotime($dateStr.' UTC');
var_dump($timestamp); //int(1674234742)
See this example for comparison.
I am alright with the basics of the php date manipulation functions, but I still get confused from time to time, partially because I don't know all of the rules firmly.
Right now I am dealing with a problem where I have a function that is going to save some data in a database. One of the data items is a date. Normally it is pretty easy for me to figure out how to convert it to the right format for the MySQL statement. However in this case the string could be in one of two different formats:
m/d/Y
or
m/d/Y h:iA
I need to be able to convert either to 'Y-m-d' and I need to know WHICH of the two formats I received. Is there a straight forward way to this? Like some sort of:
if (is_format('m/d/Y', $date)){
...
}
Thanks for the help.
Use DateTime::createFromFormat for each of your two formats in turn. It returns false on failure so you will know which call succeeded, and you get date/time validation as a bonus.
After creating the DateTime object use format to turn it into your preferred representation.
Goal: Convert any local date to the according ISO date
My Approach: http://codepad.viper-7.com/XEmnst
strftime("%Y-%m-%d",strtotime($date))";
Upside: Converts a lot of formats really well
Downside / Problem: Converts strings and numbers that are obviously not a date. E.g.
strftime("%Y-%m-%d",strtotime("A")) => 2012-10-29
strftime("%Y-%m-%d",strtotime("1")) => 1970-01-01
Questions:
Is there a better way to identify and convert dates to ISO dates?
Do you know of any library / regex that is capable of do so in php?
PHP's strtotime() function already does a best-effort attempt at taking an arbitrary string and working out what date format it is.
I dislike this function for a number of reasons, but it does do a reasonable job of working things out, given a string of unknown date format as input.
However, even strtotime()'s best efforts can never be enough, because arbitrary date formats are ambiguous.
There is no way to tell whether 05-06-07 is meant to be the 5th of June 2007 or the 6th of May 2007. Or even the 7th June 2005 (yes, some people do write dates like that).
Simple plain truth: It's impossible.
If you want your dates to be reliable in any meaningfuly way, you must abandon the idea that you'll be able to accept arbitrary input formats.
[EDIT]
You say in the comments that the input is coming from a variety of Excel and CSV files.
The only hope you have is if each of those files is consistent in itself. If you know that a file from a given source will have a given input format, you can write a custom wrapper for each file type that you import, and process it for that format. This is a solution I've used myself in the past, and it does work as long as you can predict the format for the file you're processing.
However, if individual files contain unpredictable or ambiguous dates, then you are out of luck: You have an impossible task. The only way you'll avoid having bad data is to kick back to the suppliers of the files and ask them to fix their data.
I think the problems will really arise when faced with dates such as 5-6-2012 when it is unclear whether you are dealing with 5th June, or 6th May and you could be taking input from European countries where DD MM YYYY is the norm.
If you are analyzing just one input field, then you might have a chance of detecting the delimeters and splitting the string up looking for what might look like a real date.
In this case the PHP function checkdate might come in handy as a last ditch double check.
Be aware also that Mysql (if this is where the data is heading) is also quite lenient about what it will put into a DATE field, the delimeters, the absence of leading zeros etc. But still, you have to get the Y M D order correct for it to have a chance.
I suppose the ultimate answer is to disallow free-text input for dates, but give them pickers - but of course you may not be in a position to influence the incoming date ...
Is there a way to specify your own date pattern besides the included ones (small, medium, full). The main point here is that it should work with i18n. I've tried a couple of things but I couldn't get it to work...
Yii::app()->dateFormatter->format("l d/m/Y",$slide->date_start);
I know about strftime but the problem here is that different hosting providers use different locale string... and you have to customize it...
I'm looking for an elegant way of doing this.
I'd like to display the date in l d/m/Y form...
Update:
Never mind... I've just found out that dateFormatter doesn't use standard php date format...
I think you should measure time solely in Unix Time because Timezones & date formats are a presentation-layer problem. Unix time is always UTC & It's a single number, so easier to pass around in code.
As far the problem of "hosting providers use different locale string", just ask the user his timezone & display according to that. far less error-prone than trying to guess.
For date formatting, have a look at YII's format()
Hope it answers your question
Here's a related yii forum discussion
The yii forum solution worked for me to avoid raw SQL NOW() statements but still produce database-friendly date strings with PHP date() and time() functions which otherwise return integers.
In protected/config/main.php:
...
'params'=>array(
'mysqlDateTimeFormat' => 'Y-m-d H:i:s', # ':u' adds microsecond precision,
...
Then, wherever you want to put a date-time string into a model field use
$myModel->myDate = date(Yii::app()->params['mysqlDateTimeFormat']);
Obviously you can enter the date/time format into the date (or time) functions directly if you prefer.
strtotime("25/03/1957") returns false. what will satisfy all of these date formats? i can't imagine how long it would take to actually make my own, so i hope there's already one out there you know of.
thanks!
Considering some dates are valid but can point to two different actual dates, no function will ever be able to "guess" the right format at all times...
To help with that, with PHP >= 5.3, a new function has been added : date_create_from_format -- but it doesn't exist with PHP < 5.3, unfortunately...
(See also DateTime::createFromFormat)
Still, in the example you took, the year 1957 is a possible source of problems : PHP generally works with UNIX Timestamps, when it comes to dates...
And, at least on 32-bits systems, those can only represent dates between 1970 and 2038 -- as they count the number of seconds since 1970-01-01.
To avoid this problem, it's often a good idea to use the DateTime class, with which (quoting) :
The date and time information is
internally stored as an 64-bit number
so all imaginable dates (including
negative years) are supported. The
range is from about 292 billion years
in the past to the same in the future.
(It will not solve the parsing problems with PHP < 5.3 ; but it'll solve the date-range problem...)
I've found that dateTime objects support a wider range of formats than the strtotime() function, and the timezone settings of your server also make a difference; but I ended up building a function that would replace '/' with '-' before using the string to date methods. I also test for valid, then try swapping the apparent dd and mm (25-03-2001 => 03-25-2001) if invalid before testing again.