Regex

[rohit782192]

Hello Team, What the Regex for 29-December-1987. I am trying (\d{2})-(\w{.*})-(\d{4}) but getting False when do a Match. Mostly i am going wrong in Month.

[binuacs · Accepted solution]

@rohit782192  If you want to specifically mention the character "-" use "\-" so it will treat as character.

(\d{2})\-(\w+)\-(\d{4})

[rohit782192]

I want to know before the "-" sign also we need to put a "\"

[MarqueeCrew]

@rohit782192 ,

I don't know why you want to use RegEx to parse the date.  RegEx is an expensive and complex way to try to solve your need.  To separate the text to fields, you should use the - as a delimiter in a text to columns tool.  I think that @binuacs was too focused on the act of getting a solve to understand your challenge or to give you assistance to learn Alteryx.

The reading of dates in formats other than ISO 8601 standard (YYYY-MM-DD) requires the use of a DateTimeParse() function.  Date specifiers are used to explain the contents to the function.

https://help.alteryx.com/20214/designer/datetime-functions

%Y is a 4-digit year

%B is a complete month (%b is an abbreviated month)

%d is a day# of the month

DateTimeParse[YourDateField],"%d-%B-%Y")

If the date doesn't work, you'll see conversion errors in the log and the output will be Null()

Cheers,

Mark

[rohit782192]

I echo with you but we have to be mastered in everything.

First come only in mind was regex and then come the other tool.

[MarqueeCrew]

Try:

29-February-2022

 cheers,

 mark

[rohit782192]

DateFormat	Date	Month	Year
29-Dec-87	29	December	1987
29-February-2022	29	February	2022

[Aguisande]

IMHO, "mastering everything" involves not only knowing how to use a tool. It also is about forward thinking, taking the best of the tools you have at your disposal.

This post is exactly the representation of it.

BTW, a real master, teaches others how to get to that master state.

[rohit782192]

That Awesome, I will try to use most of the Tool available in Alteryx.

Thanks for Support.

[MarqueeCrew]

@rohit782192 ,

Let's take a close look at your expression to find the cause of the problem:

Regex_Match([Date Field],"(\d{2})-(\w{.*})-(\d{4})")

This should return 0/False on your input string.  But if written properly, will return TRUE.

\w{.*} means something entirely different than you think.

Here is what it means (regex101.com):

\w matches any word character (equivalent to [a-zA-Z0-9_])
{ matches the character { with index 12310 (7B16 or 1738) literally (case sensitive)
. matches any character (except for line terminators)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
} matches the character } with index 12510 (7D16 or 1758) literally (case sensitive)

if you wanted to match multiple word characters (using PERL form of RegEx) you can still use \w, but that includes numbers.  I think that you only want letters.  If you're case-insensitive, you'll be fine with \l or \u (lower or uppercase letters).  Or you can define the set of characters as an uppercase followed by lowercase letters (you'll turn case-sensitivity on).

Essentially you want to find:

A group of 2 numbers followed by a dash followed by a series of letters (letters only)  and let's assume that you only match if it is 3 or more total letters followed by a dash followed by exactly 4 numbers.

Regex_Match([Date Field],"(\d{2})-([a-z]{3,})-(\d{4})")

This is interpreted as (regex101.com):

1st Capturing Group (\d{2})
     \d matches a digit (equivalent to [0-9])
     {2} matches the previous token exactly 2 times
     - matches the character - literally
2nd Capturing Group ([a-z]{3,})
     Match a single character present in the list below [a-z]
     {3,} matches the previous token between 3 and unlimited times, as many times as 
     possible, giving back as needed (greedy)
     a-z matches a single character in the range between a and z
     - matches the character - literally
3rd Capturing Group (\d{4})
     \d matches a digit (equivalent to [0-9])
    {4} matches the previous token exactly 4 times

That is a more complete RegEx explanation for you.

Cheers,

Mark

@jarrod