B R commands
Her kommer en liste over de mest anvendte kommandoer i R.
I foerste omgang kan du benytte denne hjemmeside med oversigt over R kommandoer.
Siden her kommer til at ligne den på linket men er nedenunder ikke færdig.
This chapter contains a brief overview of some of the most common functions we are using in our courses. Another page you might useful is www.statmethods.net that contains a short and clear presentation of many of the commands given below.
Indlæs SundBy data fra web
d <- read.csv("https://biostat.ku.dk/R/data/sundby0_English.csv")virker det ikke (for enkelte RegionH computere kan der være problemer), så følg fremgangsmåden beskrevet i kap 4.3. Eksemplerne i tabellerne nedenfor virker på SundBy data.
B.1 Viewing data
| Command | Description.and.examples |
|---|---|
head( x, n)
|
Prints the first 6 lines of a vector or a data frame.
The additional argument n specifies the number of lines to be
printed.
head( d$wgt ), head( d ) or head( d, 12 )
|
View( x )
|
Shows a data frame in spreadsheet style. |
subset( x, subset )
|
Returns a subset of a data frame with rows fulfilling the
logical condition specified in the subset argument.
subset( d, wgt>100 ) or subset( d, wgt==65 )
|
B.2 Data manipulations
| Command | Description |
|---|---|
cut( x, breaks, labels )
|
Divides a numeric variable x into categories. Cut points are specified in the breaks argument. The labels argument is used to specify informative category names. More details in Section
5.4.2. Example: cut( d$age, breaks=c(17,45,65,88), levels=c('young','middle aged','older'))
|