R: Stem-and-leaf


I. Basic Stem-and-leaf
We will construct a stem-and-leaf graph of the dist variable from the cars dataset. The following code gives us a chance to see the first 6 rows of the cars dataset.
> ### Lets look at first 6 rows of cars data set
> head(cars)
  speed dist
1     4    2
2     4   10
3     7    4
4     7   22
5     8   16
6     9   10

 

Next, we are going to create a new d variable that will represent the distance data from the cars dataset. Then we will use the stem() function to construct a basic stem-and-leaf plot of the d variable.

> # Create new variable d
> d = cars$dist
> 
> # Construct stem-and-leaf of d
> stem(d)

  The decimal point is 1 digit(s) to the right of the |

   0 | 24004678
   2 | 002466668822244466
   4 | 002668024466
   6 | 046806
   8 | 04523
  10 | 
  12 | 0

 

II. scale Parameter
The scale parameter can be used to expand the scale of the plot. A value of scale=2 will split the stems and cause the output to be roughly twice as long as the default. 
> stem(d, scale = 2)

  The decimal point is 1 digit(s) to the right of the |

   0 | 24
   1 | 004678
   2 | 0024666688
   3 | 22244466
   4 | 002668
   5 | 024466
   6 | 0468
   7 | 06
   8 | 045
   9 | 23
  10 | 
  11 | 
  12 | 0

 

 A value of scale=4 will split the stems and cause the output to be roughly four times as long as the default. 

> stem(d, scale = 4)

  The decimal point is 1 digit(s) to the right of the |

   0 | 24
   0 | 
   1 | 004
   1 | 678
   2 | 0024
   2 | 666688
   3 | 222444
   3 | 66
   4 | 002
   4 | 668
   5 | 0244
   5 | 66
   6 | 04
   6 | 68
   7 | 0
   7 | 6
   8 | 04
   8 | 5
   9 | 23
   9 | 
  10 | 
  10 | 
  11 | 
  11 | 
  12 | 0

 

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