2.1 简介

qplot的意思是快速作图（quick plot）。

qplot是一种快捷方式，如果您已习惯于使用基础plot()，则可以使用它。它可以使用一致的调用模式快速创建许多不同类型的图。

qplot(x, y, ..., data, facets = NULL, margins = FALSE, geom = "auto", xlim = c(NA, NA), ylim = c(NA, NA), log = "", main = NULL, xlab = NULL, ylab = NULL, asp = NA, stat = NULL, position = NULL)

2.2 数据集

> head(diamonds)
# A tibble: 6 x 10
  carat cut       color clarity depth table price     x     y     z
  <dbl> <ord>     <ord> <ord>   <dbl> <dbl> <int> <dbl> <dbl> <dbl>
1 0.23  Ideal     E     SI2      61.5    55   326  3.95  3.98  2.43
2 0.21  Premium   E     SI1      59.8    61   326  3.89  3.84  2.31
3 0.23  Good      E     VS1      56.9    65   327  4.05  4.07  2.31
4 0.290 Premium   I     VS2      62.4    58   334  4.2   4.23  2.63
5 0.31  Good      J     SI2      63.3    58   335  4.34  4.35  2.75
6 0.24  Very Good J     VVS2     62.8    57   336  3.94  3.96  2.48

A dataset containing the prices and other attributes of almost 54,000 diamonds. The variables are as follows:

• price: price in US dollars (\$326–\$18,823)
• carat: weight of the diamond (0.2–5.01)
• cut: quality of the cut (Fair, Good, Very Good, Premium, Ideal)(均匀、良好、非常好、优质、理想)
• color: diamond colour, from D (best) to J (worst)
• clarity: a measurement of how clear the diamond is (I1 (worst), SI2, SI1, VS2, VS1, VVS2, VVS1, IF (best))
• x: length in mm (0–10.74)
• y: width in mm (0–58.9)
• z: depth in mm (0–31.8)
• depth: total depth percentage = z / mean(x, y) = 2 * z / (x + y) (43–79)
• table: width of top of diamond relative to widest point (43–95)

抽样：

set.seed(1410)  # 让样本可重复

dsmall <- diamonds[sample(nrow(diamonds), 100), ]

2.3 基本用法

ggplot2（2） 从qplot开始入门

原文：https://www.cnblogs.com/dingdangsunny/p/12340894.html