Without using a third party module, what steps would I need to take to convert this:
<<"Mon, 17 Feb 2014 11:07:53 GMT">>
Into this?:
[17, 2, 2014, 10, 07, 53]
Most of the answers I've Googled suggest using a library.
So far, I suspect I'd get somewhere by pattern matching the formatted date string.
Something like:
<<_:5/binary, Date:2/binary>> = <<"Mon, 17 Feb 2014 11:07:53 GMT">>...
Which I think should produce the following 'match'
Date = 17...
That's based on an idea found here - https://groups.google.com/forum/#!topic/erlang-programming/OpXSqt3U86c - Is this a good approach?
Are there any BIF's or modules that can help with this?
And furthermore, how would I convert/map "Feb" to an integer?
Let's try that in the shell:
1> <<_:5/binary, Date:2/binary>> = <<"Mon, 17 Feb 2014 11:07:53 GMT">>.
** exception error: no match of right hand side value <<"Mon, 17 Feb 2014 11:07:53 GMT">>
Right, we need to match the rest of the binary at the same time:
2> <<_:5/binary, Date:2/binary, Rest/binary>> = <<"Mon, 17 Feb 2014 11:07:53 GMT">>.
<<"Mon, 17 Feb 2014 11:07:53 GMT">>
3> Date.
<<"17">>
So now Date is a binary containing the bytes for the ASCII digits 1 and 7. We can convert that to a number with binary_to_integer:
4> binary_to_integer(Date).
17
As for the conversion of month names to integers, the usual way to do something like that is with a function:
month_name_to_integer("Jan") -> 1;
month_name_to_integer("Feb") -> 2;
...
month_name_to_integer("Dec") -> 12.
You may use tempo library for datetime formatting and parsing.
Bin = <<"Mon, 17 Feb 2014 11:07:53 GMT">>,
L = binary_to_list(Bin),
{match, Res} =
re:run(L, "[0-9]+", [global, {capture, all, list}]),
[list_to_integer(X) || [X] <- Res].
the output is:
[17,2014,11,7,53]
Why suffering? Why not third party module?
I am use erlware_commons
ec_date:parse("Mon, 17 Feb 2014 11:07:53 GMT").
