5 Data Formats and Types in R
5.1 Introduction
Like in Excel, data can be of different types.
5.2 Important R data types
| Type | Short | Description | Example(s) |
|---|---|---|---|
| Numeric (double) | <dbl> |
Floating point number | 3.14159 |
| Character | <char> |
Character (text) string | "S1P d18:1", "BQC" |
| Logical | <lgl> |
True or False, 1 or 0 | TRUE; FALSE |
| Integer | <int> |
Number without digits | 3L; 7011L; -13L |
| Factor | <fct> |
Categorical data | BQC; TQC; SPL |
| Date | <dt> |
Date | 2022-01-31 |
| Time | <tm> |
Time | 13:15; 1:15 pm |
| Datetime | <dttm> |
Date + Time | 2022-01-31 13:15 |
5.3 Converting Data Types
| Type | Functions | Example(s) |
|---|---|---|
| to Number | as.numeric() |
as.numeric("3.14") |
| to Text | as.character() |
as.character(3.14) |
| to Factor | factor()as.factor()forcats::as_factor() |
as.factor(c("TQC", "SPL", "TQC")factor( x = c("TQC", "SPL", "TQC"), levels = c("TQC", "SPL" ) )
|
| to DateTime |
lubridate package |
lubridate::as_datetime("31-12-2022 13:15") |
5.4 Important R data formats
| Type | Description | Example(s) |
|---|---|---|
| Vector | Vector (series) of values. All values are of the same data type (see below) | c(1,2,3,4)c("TQC", "BQC", "SPL")c(TRUE, FALSE) |
| Matrix | 2-dimensional set of values. All values are of the same data type | matrix(data = c(1:2),nrow = 2,ncol = 3)matrix(data = c("BQC", "SPL"),nrow = 2,ncol = 3) |
| Data Frame Tibble |
Table with columns that can have different data types | tibble(No = c(1,2,3), Sample = c("A", "B", "C")) |
| List | Series of objects, that can be of different types, including e.g. tables | list( Studysite = c("NUH", "SGH"), Cohort = tibble(No = c(1,2), Size = c(110,332))) |