Get the date from txt-line

masimies

Hi,
Didn't find any match for this problem from forums.
I have text-column in table like 1612345100000098 3000067201604095678
In context, there is date included as number-series. In this sample like 20160409. With date("Ymd")-format.

I need to pick it up to variable, what i can then add to other table as date-value.

There could be used year as starting-letters, but then there is a need to put more code or queries for ensure the correct year.

Is this possible with PHP?

Weedpacket

How do you know which bit is the date?

masimies

It starts always with year. So the pattern is like Ymd

laserlight

masimies wrote:
It starts always with year. So the pattern is like Ymd

Sure, but consider: 1612040900000098 3000067201604095678. In this sample, scanning from the left, the first plausible date in that format is 16120409. Is that the correct date instead of 20160409 which is also present? Why, or why not?

In other words, just saying that the pattern is Ymd may not be precise enough. What happens if more than one substring matches the Ymd pattern for valid values Y, m and d?

masimies

Year is always starting like 2016,2017,2018 etc. There is a need to grab the date. To ensure it, if there could be 2 string matching the date, can be add syntax what chooses the correct one. Like if the second date is 20150204. If there is 2 starting with 2016, that's bad luck....

masimies

And if this is not be easy task, the string what includes date is not standard length. Cannot just remove amount of characters from left or right.

laserlight

masimies wrote:
Year is always starting like 2016,2017,2018 etc.

What about the year 3001? Look, you have to be precise. You must specify exactly, with no room for uncertainty, unless the uncertainty is inherent such that you must accept some non-zero margin of error. The use of "etc" implies that you haven't thought through the requirements clearly, and if you haven't, whatever we suggest might be wrong because there might be some requirement that we don't know about.

masimies wrote:
There is a need to grab the date. To ensure it, if there could be 2 string matching the date, can be add syntax what chooses the correct one. Like if the second date is 20150204.

Syntax is easy, trivial even. The question here is the requirements and the corresponding logic. You cannot just give an example "Like if the second date is 20150204" without explaining why you would choose one date over the other if there are two possible date candidates. I can guess that you want the most recent date, but what if my assumption is wrong?

masimies wrote:
If there is 2 starting with 2016, that's bad luck....

So what do you intend to do if there are indeed two dates starting with 2016? If you can just throw your hands in the air and say "that's bad luck", then I have a simple solution for you for your entire question: don't do this at all, just say "that's bad luck" 😉

masimies wrote:
the string what includes date is not standard length.

So, what are the possible lengths, and how would you interpret the strings with such lengths? It might also help to tell us how does this data come about in the first place.

masimies

Ok. First i only put question of, how to just grab the date from text-row. I try to put simple question, and get simple proposals to do it, because if there is too much functions, code could be gone complex.
The txt-file is bank statement. I read it to table, row by row. In same time, code checks, if there is invoice-number matching to not paid invoice, and mark invoice as "Hey, im in this statement"
Next step is, that i have now targeted rows with "Check the paid amount". At this point, code do as it should do. But i need the paid date still for interest-invoice.

Meanwhile, i did able to find the date with giving correct year before, with this syntax:
$finddate=strstr($statement, ''.$year.'');

Result is: "2016040956774589398"

So i need only 8-characters, and all others can be cleared from right. ->It doesn't matter, how long the row is then.

laserlight

masimies wrote:
First i only put question of, how to just grab the date from text-row. I try to put simple question, and get simple proposals to do it, because if there is too much functions, code could be gone complex.

If you tell us the exact input format, then it could be rather simple. You didn't specify the input format (only the date format in rather vague terms, and then you said that even that might vary without specifying exactly how), so it is not simple. You're basically saying: given an arbitrary string of numbers, identify an arbitrary date from within it that matters to me. That's inherently complex with some element of uncertainty.

masimies wrote:
Meanwhile, i did able to find the date with giving correct year before, with this syntax:
$finddate=strstr($statement, ''.$year.'');

Result is: "2016040956774589398"

But that's pretty iffy: what if "2016" just happens to be part of say, some other part of the string? You can adapt this by verifying that the substring constitutes a valid date, and if not, continue the search for the next instance of 2016. But, what happens say at the start of 2017? Could there be a problem where the year should have been 2016, but the algorithm only searches for 2017?

masimies

That row, what has been inserted to table, includes invoice-number. Then it is "unique", with only one date, what is paid-date. All other rows are not included this date-gabbing function, and we check only one invoice in time. The year, what come with submit is due-date, so it is close enough i assume.

masimies

And the final resolution was:
$pd=strstr($statement, ''.$year.'');
$pdd=substr($pd, -0, 8);
$paiddate=date("Y-m-d", strtotime($pdd));

Result is 2016-04-09

Just what i need for. But im still left thinking, is it possible do with less functions.