Hello,
The best way to plot in R is using {ggplot2}, check out its website here:
For your specific data, what do you want the bar chart to show? I've taken a stab at it below assuming you want A and B as separate bars.
library(ggplot2)
library(dplyr)
#>
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#>
#> filter, lag
#> The following objects are masked from 'package:base':
#>
#> intersect, setdiff, setequal, union
library(tidyr)
A = c(0.7986, 0.5456, 0.3730, 0.8544, 0.6092, 0.3244, 0.3134, 0.8736, 0.4532)
B = c( 0.9184, 0.6754, 0.9434, 0.3818, 0.6732, 0.8198, 0.5276, 0.8102, 0.4010, 0.9252, 0.3116)
dat <- tibble(a = c(A, NA, NA), b = B) %>%
mutate(n = row_number()) %>%
pivot_longer(-n)
ggplot(dat, aes(x = n, y = value, fill = name)) +
geom_col(position = "dodge")
#> Warning: Removed 2 rows containing missing values (geom_col).

Created on 2022-05-30 by the reprex package (v2.0.1)