In this article, I will explain how to sort or order a table by Frequency (Freq) in R. Table in R is used to represent the data with the column/variable name and the frequency of how many times each is repeated. By using order() and arrange() functions we can sort the table by ascending order, and descending order in R.
1. Quick Examples of Sorting Table
Following are quick examples of how to sort tables.
# Create Vector with repeated values
vec <- c(letters[5:12], letters[7:10], letters[9:10])
vec
# Convert vector to table
tab <- table(vec)
# Sort table in ascending order
sorted_tab <- tab[order(tab)]
sorted_tab
# Sort table in descending order
sorted_tab <- tab[order(tab,decreasing = TRUE)]
sorted_tab
# Using dplyr
sorted_tab <- tab %>%
as.data.frame() %>%
arrange(desc(Freq))
sorted_tab
First, let’s create a character vector in R and convert it to the table by using table() function.
# Create Vector with repeated values
vec <- c(letters[5:12], letters[7:10], letters[9:10])
vec
# Convert vector to table
tab <- table(vec)
Yields below vector
And the below R table. Note that the table contains the value and the frequency of the value (how many times each value is repeated).
2. R Sort Table in Ascending
By using R base function order() we can sort the table in ascending order. This function takes the table indices, so we have to use [] – index and inside this, we can apply the order() function.
# Sort table in ascending order
sorted_tab <- tab[order(tab)]
sorted_tab
Yields below output.
3. R Sort Table in Descending
Similarly, you can also use R base order() function along with decreasing = TRUE param to sort the table in descending order.
# Sort table in descending order
sorted_tab <- tab[order(tab,decreasing = TRUE)]
sorted_tab
Yields below output.
4. Sort Table using dplyr
Another way to order the table in R is by converting the table into DataFrame and using the dplyr arrange() function to sort the dataframe.
The arrange() function from dplyr package is also used to arrange the values in an ascending or descending order. To use arrange() function, you have to install dplyr first using install.packages(‘dplyr’) and load it using library(dplyr).
All functions in dplyr package take data.frame as a first argument. When we use dplyr package, we mostly use the infix operator %>% from magrittr, it passes the left-hand side of the operator to the first argument of the right-hand side of the operator. For example, x %>% f(y) converted into f(x, y) so the result from the left-hand side is then “piped” into the right-hand side.
# Using dplyr
sorted_tab <- tab %>%
as.data.frame() %>%
arrange(desc(Freq))
sorted_tab
Yields below output.
5. Matrix to Table and Sort
Let’s take a little complex example and see how to sort the table in R.
# Create table
tab <- matrix(c(6, 3, 2, 9, 6, 34, 26, 4, 5), ncol=3, byrow=TRUE)
colnames(tab) <- c('col1','col2','col3')
rownames(tab) <- c('row1','row2','row3')
tab <- as.table(tab)
tab
Yields below output.
Now sort the table by Frequency Freq column.
# Sort table by converting to DataFrame
tab2 <- tab %>%
as.data.frame() %>%
arrange(desc(Freq))
tab2
I will leave this to you to run and explore the output.
Conclusion
In this R article, you have learned how to sort/order the table by using the order() and arrange() function. By using these functions you have also learned to sort tables in ascending or descending order.
Related Articles
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- R Sort by Multiple Columns
- How to Sort by Date in R?
- R Sort DataFrame Rows by Column Value
- Order DataFrame by one descending and one ascending column in R
- R Sort Vector
- Reorder Columns of DataFrame in R
