r - 有条件地替换 R 中的分类值

Question

我是 R 的新手，一直在这个论坛上咨询我以前遇到的一些 R 问题。但是，我似乎无法找到当前问题的答案。

我有一个包含多列的大数据集。我想根据另一列中的值替换一列中的某些值。这是一个示例:

organization                                    organization_type                
[1,] "Human Relief Foundation"                  "NGO"                            
[2,] "Management Systems International"         "Other"                          
[3,] "World Vision"                             "NGO"                            
[4,] "European Disaster Volunteers"             "NGO"                            
[5,] "Management Systems International"         "Other"                          
[6,] "International Committee of the Red Cross" "Red Cross/Red Crescent Movement"
[7,] "International Committee of the Red Cross" "Red Cross/Red Crescent Movement"
[8,] "Development Alternatives"                 "Consultancy"                    

上面的数据集在 organization_type 下显示了“其他”的值“国际管理系统”。我想将“其他”替换为“咨询”。我该怎么做？

我已经按照另一个论坛中的建议尝试了以下方法，但它只保留了过滤后的数据:

library(dplyr)

data_df <- data_df %>% filter(organization == "Management Systems International" 
           & organization_type == "Other") %>%  
           mutate(organization_type = "Consultancy")

有没有办法在 R 中“取消过滤”数据，使原始数据条目与过滤后的数据一起出现？ Excel 可以做到这一点，但很难在 Excel 中处理大数据集。

谢谢!

Answer 1

使用 data.table 包，您可以按如下方式执行此操作:

# Install if necessary
if (!require("data.table")) install.packages("data.table")
# Load the data.table package
library(data.table)

# Convert data_df to a data.table 
data_dt <- data.table(data_df) %>%
  # Where organization_type equals 'Other', replace organization_type to 'Consultancy'
  .[organization_type == "Other", organization_type := "Consultancy"]

# Print result
print(data_dt)

结果:

                               organization               organization_type
1:                  Human Relief Foundation                             NGO
2:         Management Systems International                     Consultancy
3:                             World Vision                             NGO
4:             European Disaster Volunteers                             NGO
5:         Management Systems International                     Consultancy
6: International Committee of the Red Cross Red Cross/Red Crescent Movement
7: International Committee of the Red Cross Red Cross/Red Crescent Movement
8:                 Development Alternatives                     Consultancy