更改 R 中字段的名称

Question

我是这个小组的新成员（也是一个相当新的 R 用户），我有一个问题。我有一个 data.table 这样的

Date             V2                       Deal Type
-----------------

1: 2009-1       Public sector bank        Corporate Bond-Investment-Grade                 
2: 2009-1       Private sector bank       Corporate Bond-Investment-Grade                 
3: 2009-7       Private sector industrial Corporate Bond-Investment-Grade                   
4: 2009-1       Private sector bank       Corporate Bond-Investment-Grade                  
5: 2009-1       Private sector bank       Covered Bond                         
6: 2009-1       Public sector bank        Corporate Bond-Investment-Grade                 
7: 2009-1       Private sector bank       Corporate Bond-Investment-Grade

问题是如何更改 V2 列中变量（和变量）的名称。例如，我希望 "public sector bank" 和 "private sector bank" 在新列中显示为 "financial"，"private sector industrial" 和 "public sector industrial" 显示为 "non-financial"。希望我已经足够清楚了。非常感谢您的帮助。

Answer 1

假设您的数据框名为 df，您可以执行以下操作：

df <- read.csv("data.csv", stringsAsFactors=FALSE)

df$newColumn[df$V2 == "Public sector bank" | df$V2 == "Private sector bank"] <- "financial"
df$newColumn[df$V2 == "Public sector industrial" | df$V2 == "Private sector industrial"] <- "non-financial"

或者如果您确定您的 V2 字段中包含单词 "bank" 和 "industrial"，这就是您如何确定在新列中调用值的方式，您可以这样做：

df$newColumn[grepl("bank", df$V2)] <- "financial"
df$newColumn[grepl("industrial", df$V2)] <- "non-financial"

这对数据表也同样有效

Answer 2

如果 DT 是你的 data.table

`DT[,':='(V3 = ifelse(V2 %in% c("Public sector bank","Private sector bank"),"Non financial","Financial")`]

标准化文本字段通常是一个好习惯，因此您可以考虑：

DT[,':='(V3 = ifelse(tolower(gsub(" ","",V2)) %in% c("publicsectorbank","privatesectorbank"),"Non financial","Financial")]

希望对你有帮助，我也推荐https://s3.amazonaws.com/assets.datacamp.com/img/blog/data+table+cheat+sheet.pdf

Answer 3

replace() 在这种情况下可以派上用场。假设您的数据框为 DF，您的新列为 V2new:

# Creating new column V2new and replacing "Public/Private sector bank" to "financial" 
DF$V2new <- replace(DF$V2 ,DF$V2 =="Public sector bank"|DF$V2=="Private sector bank","financial") 
# Replacing "Public/Private sector industrial"  from V2new to "non-financial"
DF$V2new <-  replace(DF$V2new ,DF$V2new =="Public sector industrial"|DF$V2new =="Private sector industrial","non-financial")

更改 R 中字段的名称

Change the name of fields in R

r

variables

names