从文本文件 value.var 错误将数据框重塑为矩阵

Question

我有一个与这里非常相似的问题：Reshape three column data frame to matrix ("long" to "wide" format)

除非我从文本文件中获取数据，并且我正在尝试使用 reshape2 库和 dcast 方法

这是我的文本文件：

'Group','LiteracyLevel','Frequency'
'Shifting','Illerate',114
'Shifting','Primary',10
'Shifting','AtLeastMiddle',45
'Settled','Illerate',76
'Settled','Primary',2
'Settled','AtLeastMiddle',53
'Town','Illerate',93
'Town','Primary',13
'Town','AtLeastMiddle',208

应该改成这种格式，因为我想在上面使用barplot(as.matrix(data))。

'Group','Illerate','Primary','AtLeastMiddle'
'Shifting',114,10,45
'Settled',76,2,53
'Town',93,13,208

我不知道为 dcast 的 value.var 部分输入什么。我假设它的频率。我目前重塑数据的尝试如下所示：

> data <- read.csv("ex3-39.txt", header=TRUE)

> dcast(data, data$Group~data$LiteracyLevel, value.var="X.Frequency")
Error: value.var (X.Frequency) not found in input

> dcast(data, data$Group~data$LiteracyLevel, value.var="Frequency")
Error: value.var (Frequency) not found in input

> dcast(data, data$Group~data$LiteracyLevel, value.var="data$X.Frequency")
Error: value.var (data$X.Frequency) not found in input

> dcast(data, data$Group~data$LiteracyLevel, value.var=data$X.Frequency)
Error: value.var (1141045762539313208) not found in input
In addition: Warning message:
In if (!(value.var %in% names(data))) { :
  the condition has length > 1 and only the first element will be used

> dcast(data, data$Group~data$LiteracyLevel, value.var=Frequency)
Error in match(x, table, nomatch = 0L) : object 'Frequency' not found

Answer 1

这有帮助吗

library(reshape2)
data<-read.csv("filename.csv",quote = "'")
dcast(data, data$Group~data$LiteracyLevel, value.var="Frequency")

这将输出为

  data$Group AtLeastMiddle Illerate Primary
1    Settled            53       76       2
2   Shifting            45      114      10
3       Town           208       93      13

我认为您错过了quote="'" 参数并且您的列名的格式为

"X.Group." "X.LiteracyLevel." "X.Frequency."

如果您不想使用quote="'" 参数，请使用：

dcast(data, data$X.Group.~data$X.LiteracyLevel., value.var="X.Frequency.")

这将给出输出

  data$X.Group. 'AtLeastMiddle' 'Illerate' 'Primary'
1     'Settled'              53         76         2
2    'Shifting'              45        114        10
3        'Town'             208         93        13

这是为了好玩。要在此代码之后创建一个漂亮的条形图，请不要投射整个矩阵。您应该将第一列作为图例

让final_data 包含重构后的数据。对于矩阵跳过第一列并将其用作图例。

barplot(as.matrix(final_data[,2:4]),legend=final_data$"data$Group")

这将给出一个很好的图表

Answer 2

# Just to make sure we're dealing with the same data...
df <- read.csv(quote="'",text="'Group','LiteracyLevel','Frequency'
'Shifting','Illerate',114
'Shifting','Primary',10
'Shifting','AtLeastMiddle',45
'Settled','Illerate',76
'Settled','Primary',2
'Settled','AtLeastMiddle',53
'Town','Illerate',93
'Town','Primary',13
'Town','AtLeastMiddle',208")
df
#                     Group LiteracyLevel Frequency
# 1                Shifting      Illerate       114
# 2                Shifting       Primary        10
# 3                Shifting AtLeastMiddle        45
# 4                 Settled      Illerate        76
# 5                 Settled       Primary         2
# 6                 Settled AtLeastMiddle        53
# 7                    Town      Illerate        93
# 8                    Town       Primary        13
# 9                    Town AtLeastMiddle       208

library(reshape2)
dcast(df, Group~LiteracyLevel)
#                     Group AtLeastMiddle Illerate Primary
# 1                 Settled            53       76       2
# 2                Shifting            45       NA      NA
# 3                    Town           208       93      13
# 4                Shifting            NA      114      10

问题是您需要在公式中指定列名（引用data），而不是列。当您像以前一样指定列时，例如df$Group 结果向量未命名。

names(df)
# [1] "Group"         "LiteracyLevel" "Frequency"    
names(df$Group)
# NULL