Detecting and changing date format.

[moinyuso96]

I have a field "Date" as below. However, there are some inconsistency in the date format.  How can I get the "30/1/2021" and change it to "1/30/2021" following the rest of the date format?

Date

4/16/2021

3/31/2021

2/28/2021

30/1/2021

2/13/2021

[richgalloway · Accepted solution]

First, have a serious chat with the developers about which date format to use and stick with it.

It's possible to check the date and guess if the format is correct or not, but it's not foolproof.  Hence, the chat.

See if this query helps.

| makeresults | eval _raw="Date
4/16/2021
3/31/2021
2/28/2021
30/1/2021
2/13/2021" | multikv forceheader=1
```Everything above just sets up test data.  Don't include in the real query```
```Extract the first number, which should be a month number```
| rex field=Date "(?<mon>\d+)"
```Get the current month number```
| eval currMon=strftime(now(), "%m")
```If the mon number is too big then assume it's a date; 
if it's bigger than the current month then assume it's a date;
otherwise, use Date```
| eval newDate=if(mon>12 OR mon>currMon, strftime(strptime(Date,"%d/%m/%Y"), "%m/%d/%Y"), Date)
| table Date newDate