What is the usage of the table function in the R langua…
The table function in the R language is used to create a frequency table, which counts and displays the number of occurrences of each element in a given vector. Its basic usage is as follows:
display the contents/ values in table x
In this case, x can be a vector or a factor, which can be numeric, character, or logical. The table function will return a table listing the frequency of each element in x. The rows of the table represent the elements in x, while the columns represent the frequency of occurrences.
For example, suppose there is a vector x = c(1, 2, 3, 1, 2, 3, 3), you can use the table function to calculate the frequency of each element in x.
x <- c(1, 2, 3, 1, 2, 3, 3)
table(x)
The output is:
x
1 2 3
2 2 3
The results above indicate that in set X, element 1 appeared twice, element 2 also appeared twice, and element 3 appeared three times.
The table function also has some optional parameters that can be used to control the output format of the frequency table. For example, the dnn parameter can be used to specify the column names of the table.
x <- c(1, 2, 3, 1, 2, 3, 3)
table(x, dnn = "Value")
The output is:
Value
1 2 3
2 2 3
The results above are the same as before, except that the column names have been changed to “Value”. The dnn parameter can be a character vector used to specify multiple column names.
Furthermore, the table function can also be used to count the frequency of multiple vectors. For example, if there are two vectors x and y, you can use the table function to calculate their cross frequencies.
x <- c(1, 2, 3, 1, 2, 3, 3)
y <- c("A", "B", "A", "B", "B", "A", "A")
table(x, y)
The output result is:
y
x A B
1 2 0
2 0 2
3 3 0
The results above show that the combination of (1, A) occurred twice, (2, B) occurred twice, and (3, A) occurred three times, while all other combinations did not occur.
In conclusion, the table function in the R language is used to create frequency tables, which can be used to count the occurrences of elements in a vector and the cross-frequency of multiple vectors.
