Section 19 Daframe Operation
19.1 Operation on data.frame
Be careful while carrying out matrix-like operation on the data.frame
Matrix-like operation on data.frame may not give intended outcomes; it may not even show warning and error
Always select the specific column in a data.frame as a vector and then do the vector-like operation as we have seen earlier
19.2 Mathematical operation
x <- c(1:10); y <- rep(c('M','F'), each=5); z <- rep(c(T,F), length=10)
DF <- data.frame(Age=x, Sex=y, Vac=z)
x <- DF$Age
x+5
x-5
x*5
x/2
x^2
sqrt(DF$Age)
log(DF$Age)19.3 Statistical operation
x <- c(1:10); y <- rep(c('M','F'), each=5); z <- rep(c(T,F), length=10)
DF <- data.frame(Age=x, Sex=y, Vac=z)
x <- DF$Age
sum(x, na.rm = TRUE)
min(x, na.rm = TRUE)
max(x, na.rm = TRUE)
range(x, na.rm = TRUE)
mean(x, na.rm = TRUE)
median(x, na.rm = TRUE)
var(x, na.rm = TRUE)
sd(x, na.rm = TRUE)
sqrt(var(x, na.rm = TRUE))