Re^3: sort csv file on "date" column

The logic is to rearrange the date field (for example: 03/25/09) from month-day-year to year-month-day so it can be sorted by the built-in sort function without modification. The algorithm employed is the GRT (Guttman-Rosler Transform) which prepends the reformatted date to the current record, sorts the current record, and then removes the reformatted date from the beginning of the current record.

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Re^4: sort csv file on "date" column by mbm (Novice) on Apr 26, 2009 at 18:19 UTC
`ok... I wanted to know what the numbers 6, [2,0,1] actually are. It he +lps me to customize the algorithm you provided if the date field is i +n other column. ~Manjunath` [download]	[reply] [d/l]
Re^5: sort csv file on "date" column by jwkrahn (Abbot) on Apr 26, 2009 at 23:30 UTC
In your CSV file the date is in the month-day-year order. The regular expression captures those numbers using parentheses and returns a list of those three numbers in month-day-year order. The list of numbers is rearranged using a list slice so that the year is moved to the front of the list. So the original order of month-day-year (0,1,2) is changed to year-month-day (2,0,1). The date format used has every field as a two digit number so the combination of the year, month and day fields is a string 6 characters long.	[reply]