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I need to sort a data frame by date in R. The dates are all in the form of "dd/mm/yyyy". The dates are in the 3rd column. The column header is V3. I have seen how to sort a data frame by column and I have seen how to convert the string into a date value. I can't combine the two in order to sort the data frame by date.
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One thing to notice here is our DataFrame gets sorted in ascending order of dates, to sort the DataFrame in descending order we can pass an additional parameter inside the sort_values() function that will set ascending value to False and will return the DataFrame in descending order.
Here order() function is used to sort the dataframe by R using order() function based on the date column, we have to convert the date column to date with the format, this will sort in ascending order.
To sort a Python date string list using the sort function, you'll have to convert the dates in objects and apply the sort on them. For this you can use the key named attribute of the sort function and provide it a lambda that creates a datetime object for each date and compares them based on this date object.
Assuming your data frame is named d,
d[order(as.Date(d$V3, format="%d/%m/%Y")),] Read my blog post, Sorting a data frame by the contents of a column, if that doesn't make sense.
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Nowadays, it is the most efficient and comfortable to use lubridate and dplyr libraries.
lubridate contains a number of functions that make parsing dates into POSIXct or Date objects easy. Here we use dmy which automatically parses dates in Day, Month, Year formats. Once your data is in a date format, you can sort it with dplyr::arrange (or any other ordering function) as desired:
d$V3 <- lubridate::dmy(d$V3) dplyr::arrange(d, V3) If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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