[ggplot] Bar plot in R

In this post I introduce how to draw bar plots in R.

Simple Histogram in R

suppose we have data that looks like,

# A tibble: 217 × 31
   Rk    Player  Pos     Age Tm    G     GS    MP    FG    FGA   `FG%` `3P`  `3PA` `3P%` `2P`  `2PA` `2P%` `eFG%` FT    FTA
   <chr> <chr>   <chr> <dbl> <chr> <chr> <chr> <chr> <chr> <chr> <chr> <chr> <chr> <chr> <chr> <chr> <chr> <chr>  <chr> <chr>
 1 1     Precio… C        22 TOR   6     1     27.8  4.2   8.7   .481  0.8   2.7   ".31… 3.3   6.0   .556  .529   1.0   1.7
 2 2     Steven… C        28 MEM   7     5     16.3  1.3   3.0   .429  0.0   0.0   ""    1.3   3.0   .429  .429   0.9   1.6
 3 3     Bam Ad… C        24 MIA   18    18    34.1  5.8   9.7   .594  0.0   0.1   ".00… 5.8   9.7   .598  .594   3.2   4.2
 4 4     Nickei… SG       23 UTA   1     0     5.0   2.0   2.0   1.000 0.0   0.0   ""    2.0   2.0   1.000 1.000  1.0   1.0
 5 5     Grayso… SG       26 MIL   12    5     25.4  3.1   6.8   .451  1.6   4.0   ".39… 1.5   2.8   .529  .567   0.6   0.9
 6 6     Jose A… PG       23 NOP   6     0     19.5  2.7   5.5   .485  1.0   2.7   ".37… 1.7   2.8   .588  .576   1.7   2.2
 7 7     Kyle A… PF       28 MEM   12    1     18.4  2.4   4.3   .569  0.3   1.0   ".25… 2.2   3.3   .667  .598   0.9   1.5
 8 8     Gianni… PF       27 MIL   12    12    37.3  11.7  23.8  .491  0.8   3.4   ".22… 10.9  20.3  .537  .507   7.6   11.2
 9 9     Thanas… SF       29 MIL   8     0     2.5   0.3   0.4   .667  0.0   0.0   ""    0.3   0.4   .667  .667   0.1   0.4
10 10    OG Anu… SF       24 TOR   6     6     36.2  6.5   13.7  .476  2.3   6.8   ".34… 4.2   6.8   .610  .561   2.0   2.7

Use the code below to generate a historgram by age.

NBA %>% ggplot(aes(x=Age)) + geom_histogram(binwidth=1)

Note that x=Age specifies what value will go to x axis, and binwidth = 1 gives the width of every bar in the histogram. The result is below.

We can also set binwidth alternatively like below.

NBA %>% ggplot(aes(x=Age)) + geom_histogram(binwidth=3)

The result is below. Note that every bar in histogram represents interval containing three age.

Giving color to bar plot

You can use fill property to give the color of bar plot. The code below uses the column Pos, to color the bars.

NBA %>% ggplot(aes(x=Age, fill=Pos)) + geom_histogram(binwidth=1)

The result is below.

Bar plot illustrating proportion

Some times, you want to plot the proportion of properties but not the absolute value. The code below does this.

NBA %>% ggplot(aes(x=Age, fill=Pos)) + geom_bar(position='fill')

Nothe that geom_histogram is replaces to geom_bar, and the text 'fill' is given to the variable position. Giving position = 'stack' will give the same result when you use geom_historgram. The result is below.