table()

table(..., exclude = NA, useNA = c("no", "ifany", "always"))

The table() function creates contingency tables, also known as frequency tables. It counts the occurrences of each unique value in one or more vectors or factors, making it essential for exploratory data analysis and categorical data summarization. The function is part of base R and requires no additional packages.

Syntax

table(..., exclude = NA, useNA = c("no", "ifany", "always"))

Parameters

Parameter	Type	Default	Description
...	vectors/factors	required	One or more vectors or factors to cross-tabulate
exclude	character/NA	NA	Values to exclude from the table; use NA to keep NA counts
useNA	character	"no"	Controls NA handling: "no" (no NA column), "ifany" (include if present), "always" (always include)

Examples

Basic one-way table

colors <- c("red", "blue", "red", "green", "blue", "red")
table(colors)
# colors
# blue green   red 
#    2     1     3 

Two-way cross-tabulation

gender <- c("M", "F", "M", "F", "M", "F", "M", "M")
outcome <- c("pass", "pass", "fail", "pass", "pass", "fail", "pass", "fail")

table(gender, outcome)
#         outcome
# gender  fail pass
#      F     1    2
#      M     2    3

Using useNA

scores <- c(85, 92, NA, 78, NA, 88, 95)
table(scores, useNA = "ifany")
# scores
#   78   85   88   92   95 <NA> 
#     1    1    1    1    1    2 

Common Patterns

Proportions

colors <- c("red", "blue", "red", "green", "blue", "red", "green", "green")
tbl <- table(colors)
prop.table(tbl)
# colors
#  blue green   red 
#  0.25  0.375  0.375 

Margin tables

gender <- c("M", "F", "M", "F", "M", "F")
outcome <- c("pass", "pass", "fail", "pass", "pass", "fail")

addmargins(table(gender, outcome))
#         outcome
# gender   fail pass Sum
#      F      1    2   3
#      M      2    2   4
#      Sum    3    4   7

See Also

• diff()
• round()
• tapply()