如何以不同格式从R的CSV文件中读取一列值

Question

如何在R中将图例用于以下数据

ID  Gender    Age   Site      Times
1   Male      24    Facebook     10
2   Female    24    Linkedin     10
3   Male      24    Twitter      10
4   Female    24    Myspace      10
5   Male      24    Facebook     10
6   Female    24    linkedin     10
7   Male      24    Facebook     10

读取我使用过的CSV

pd.readcsv <- read.csv(file = "snsite.csv")

设计我使用的饼图

pie(pd.freq[order(pd.freq,decreasing = T)],
col = c("Blue","Green","Yellow","Brown","Green"),
border = NA, main = "Site Usage")

现在要在右上角或左上角显示图例，如何从csv文件中以不同的形式读取一列（Site）值并将其存储在变量中并在图例函数中使用？

Answer 1

我不确定从哪里获得pd.freq对象，但是假设您试图获取一个饼图，该饼图显示每个站点访问了每个站点的次数，那么就可以解决问题。

# Read dataframe, I would recommend including the stringsAsFactors = FALSE argument to your read.csv command
pd.readcsv <- read.table(text = "ID  Gender    Age   Site      Times
                                  1   Male      24    Facebook     10
                                  2   Female    24    Linkedin     10
                                  3   Male      24    Twitter      10
                                  4   Female    24    Myspace      10
                                  5   Male      24    Facebook     10
                                  6   Female    24    linkedin     10
                                  7   Male      24    Facebook     10", 
                                  header = TRUE, stringsAsFactors = FALSE)

# Convert sites to lowercase for proper aggregation
pd.readcsv$Site <- sapply(pd.readcsv$Site, tolower)

# Get vector of unique site names
sites <- unique(pd.readcsv$Site)

# Create aggregate dataframe with total times per site
pd.SumSiteTimes <- aggregate(Times~Site, sum, data = pd.readcsv)

# Create vector for colors
colors <- c("Blue","Green","Yellow","Brown","Green")

# Create pie chart
pie(pd.SumSiteTimes$Times[order(pd.SumSiteTimes$Times,decreasing = T)],
    col = colors,
    border = NA, 
    main = "Site Usage")

# Add legend to the plot
legend("topright", sites, cex = .8, fill = colors)