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Sorting a data frame is a common task in data analysis and can be easily done in R using the built-in function “order()”. This function allows the user to sort the rows of a data frame based on a specific column, either in ascending or descending order. To use this function, the user needs to specify the data frame and the column to be sorted. For example, to sort a data frame named “df” by the column “Age” in ascending order, the code would be: “df[order(df$Age),]”. This will arrange the rows of the data frame in ascending order, based on the values in the “Age” column. Similarly, to sort in descending order, the code would be: “df[order(-df$Age),]”. Other examples of sorting a data frame by a specific column can include sorting by alphabetical order, numeric values, or dates. Overall, the “order()” function in R makes sorting data frames by a specific column a simple and efficient task.
Sort a Data Frame by Column in R (With Examples)
The easiest way to sort a data frame by a column in R is to use the order() function:
#sort ascending df[order(df$var1), ] #sort descending df[order(-df$var1), ]
This tutorial provides several examples of how to use this function in practice with the following data frame:
#create data frame df <- data.frame(var1=c(1, 3, 3, 4, 5), var2=c(7, 7, 8, 3, 2), var3=letters[1:5]) #view data frame df var1 var2 var3 1 1 7 a 2 3 7 b 3 3 8 c 4 4 3 d 5 5 2 e
Example 1: Sort by One Column
The following code shows how to sort the data frame by the var1 column, both in an ascending and descending manner:
#sort by var1 ascending df[order(df$var1), ] var1 var2 var3 1 1 7 a 2 3 7 b 3 3 8 c 4 4 3 d 5 5 2 e #sort by var1 descending df[order(-df$var1), ] var1 var2 var3 5 5 2 e 4 4 3 d 2 3 7 b 3 3 8 c 1 1 7 a
Note that we can also sort by a character vector alphabetically:
#sort by var3 ascending df[order(df$var3), ] var1 var2 var3 1 1 7 a 2 3 7 b 3 3 8 c 4 4 3 d 5 5 2 e
Example 2: Sort by Multiple Columns
The following code shows how to sort the data frame by multiple columns:
#sort by var2 ascending, then var1 ascending df[order(df$var2, df$var1), ] var1 var2 var3 5 5 2 e 4 4 3 d 1 1 7 a 2 3 7 b 3 3 8 c #sort by var2 ascending, then var1 descending df[order(df$var2, -df$var1), ] var1 var2 var3 5 5 2 e 4 4 3 d 2 3 7 b 1 1 7 a 3 3 8 c