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I want to sort a data.frame by multiple columns, ideally using base R without any external packages (though if necessary, so be it). Having read How to sort a dataframe by column(s)?, I know I can accomplish this with the order() function as long as I either:
But what if I only have one vector containing multiple column names, of length that's unknown in advance?
Say the vector is called sortnames.
data[order(data[, sortnames]), ] won't work, because order() treats that as a single sorting argument.
data[order(data[, sortnames[1]], data[, sortnames[2]], ...), ] will work if and only if I specify the exact correct number of sortname values, which I won't know in advance.
Things I've looked at but not been totally happy with:
eval(parse(text=paste("data[with(data, order(", paste(sortnames, collapse=","), ")), ]"))). Maybe this is fine, but I've seen plenty of hate for using eval(), so asking for alternatives seemed worthwhile.Deducer library to do this with sortData(), but like I said, I'd rather avoid using external packages. If I'm being too stubborn about not using external packages, let me know. I'll get over it. All ideas appreciated in advance!
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You can sort pandas DataFrame by one or multiple (one or more) columns using sort_values() method and by ascending or descending order. To specify the order, you have to use ascending boolean property; False for descending and True for ascending. By default, it is set to True.
To sort the DataFrame based on the values in a single column, you'll use . sort_values() . By default, this will return a new DataFrame sorted in ascending order. It does not modify the original DataFrame.
Group By Multiple Columns in R using dplyrUse group_by() function in R to group the rows in DataFrame by multiple columns (two or more), to use this function, you have to install dplyr first using install. packages('dplyr') and load it using library(dplyr) . All functions in dplyr package take data.
To sort a DataFrame based on column names in descending Order, we can call sort_index() on the DataFrame object with argument axis=1 and ascending=False i.e.
You can use do.call:
data<-data.frame(a=rnorm(10),b=rnorm(10))
data<-data.frame(a=rnorm(10),b=rnorm(10),c=rnorm(10))
sortnames <- c("a", "b")
data[do.call("order", data[sortnames]), ]
This trick is useful when you want to pass multiple arguments to a function and these arguments are in convenient named list.
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