Partial Matching

df = data.frame("a"= letters[1:10], "abc" = 1:10)

head(df)

##   a abc
## 1 a   1
## 2 b   2
## 3 c   3
## 4 d   4
## 5 e   5
## 6 f   6

df$ab # returns the column named "abc"

##  [1]  1  2  3  4  5  6  7  8  9 10

Ploting

How did the plot function know about the x and y variables to be ploted and labeled?

plot(pressure)

plot of chunk quirkyplot

Sub-setting

When you subset with brackets by 1 column, the resultant is a numeric vector not a data.frame of length 1. You can then change it back into a data.frame if necessary.

i = iris[, 1]
class(i)

## [1] "numeric"

length(i)

## [1] 150

i2 = iris[, 1:2]
class(i2)

## [1] "data.frame"

length(i2)

## [1] 2

nrow(i2)

## [1] 150