在ggplot2条形图中排序因子 [英] ordered factors in ggplot2 bar chart

问题描述

我有一个数据框（用于简化评委，电影和评分）（评分是1星级到5星级）：

  d = data.frame（判断= c（alice，bob，alice），movie = c（玩具故事，开始，开始），评分= c （1,3,5））
  

我想创建一个条形图，其中x轴是如果我这样做的话

b

pre> ggplot（d，aes（评分））+ geom_bar（）


这个效果很好，除了这些酒吧并没有集中在每个评级上，并且每个酒吧的宽度都不理想。

如果我做了

  ggplot（d，aes（factor（rating）））+ geom_bar（）
  pre> 
 
 
恒星数量的顺序会在x轴上混乱。 （在我的Mac上，至少;出于某种原因，默认顺序在Windows机器上工作。）这是它的样子：
  
 
 
 alt =alt text> 
 
 
 
 > ggplot（d，aes（factor（rating，ordered = T，levels = -3：3）））+ geom_bar（）
  
但这似乎没有帮助。
 
 
 
如何让我的条形图看起来像上图，但是正确的排序在X轴上？
解决方案
我不确定您的示例数据框是否代表您放置的图像。你提到你的评分是1-5分，但你的图片显示-3到3分。这就是说，我认为这应该让你朝着正确的方向前进：
 
 
 
示例数据： 
 
 <$ p $ （c（alice，bob，tony），100，replace = TRUE）
，movie = sample（c（ 玩具故事，初始，他们自己的联盟​​），100，替换= TRUE）
，rating = sample（1：5，100，replace = TRUE））
  

您最接近这一点：



  ggplot（d，aes（rating））+ geom_bar（）
  

binwidth在 geom_bar 中，我们可以使条宽更合适，并将评级作为一个因素集中在标签上：



  ggplot（d，aes（x = factor（rating）））+ geom_bar（binwidth = 1）
  

如果您想在图表中加入其他变量之一（例如电影），您可以使用fill：

  ggplot（d，aes（x = factor（rating），fill = factor（movie）））+ geom_bar（binwidth = 1）
  

如果要将少量电影进行比较，将电影放在x轴上并填充评分可能更有意义：

如果这样做不能让你顺其自然，请举出更具代表性的数据集示例。我无法重新创建订购问题，但这可能是由于您发布的样本数据和您正在分析的数据存在差异。

ggplot网站也是一个很好的参考： http://had.co.nz/ggplot2/geom_bar.html

I have a data frame with (to simplify) judges, movies, and ratings (ratings are on a 1 star to 5 star scale):

d = data.frame(judge=c("alice","bob","alice"), movie=c("toy story", "inception", "inception"), rating=c(1,3,5))

I want to create a bar chart where the x-axis is the number of stars and the height of each bar is the number of ratings with that star.

If I do

ggplot(d, aes(rating)) + geom_bar()

this works fine, except that the bars aren't centered over each rating and the width of each bar isn't ideal.

If I do

ggplot(d, aes(factor(rating))) + geom_bar()

the order of the number of stars gets messed up on the x-axis. (On my Mac, at least; for some reason, the default ordering works on a Windows machine.) Here's what it looks like:

I tried

ggplot(d, aes(factor(rating, ordered=T, levels=-3:3))) + geom_bar()

but this doesn't seem to help.

How can I get my bar chart to look like the above picture, but with the correct ordering on the x-axis?

解决方案

I'm not sure your sample data frame is representative of the images you put up. You mentioned your ratings are on a 1-5 scale, but your images show a -3 to 3 scale. With that said, I think this should get you going in the right direction:

Sample data:

d = data.frame(judge=sample(c("alice","bob","tony"), 100, replace = TRUE)
    , movie=sample(c("toy story", "inception", "a league of their own"), 100, replace = TRUE)
    , rating =  sample(1:5, 100, replace = TRUE))

You were closest with this:

ggplot(d, aes(rating)) + geom_bar()

and by adjusting the default binwidth in geom_bar we can make the bar widths more appropriate and treating rating as a factor centers them over the label:

ggplot(d, aes(x = factor(rating))) + geom_bar(binwidth = 1)

If you wanted to incorporate one of the other variables in the chart such as the movie, you can use fill:

ggplot(d, aes(x = factor(rating), fill = factor(movie))) + geom_bar(binwidth = 1)

It may make more sense to put the movies on the x axis and fill with the rating if you have a small number of movies to compare:

ggplot(d, aes(x = factor(movie), fill = factor(rating))) + geom_bar(binwidth = 1)

If this doesn't get you on your way, put up a more representative example of your dataset. I wasn't able to recreate the ordering problems, but that could be due to a difference in the sample data you posted and the data you are analyzing.

The ggplot website is also a great reference: http://had.co.nz/ggplot2/geom_bar.html

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