根据另一个数据帧中的匹配条件向R中的数据帧添加列

# 创建两个数据帧df1和df2
df1 <- data.frame(ID = c(1, 2, 3, 4),
                  Name = c("Alice", "Bob", "Charlie", "David"))

df2 <- data.frame(ID = c(2, 3),
                  Age = c(25, 30))

# 使用merge()函数将df2中的Age列添加到df1中，根据ID进行匹配
merged_df <- merge(df1, df2, by = "ID", all.x = TRUE)

# 输出合并后的数据帧
print(merged_df)

# 安装并加载dplyr包
install.packages("dplyr")
library(dplyr)

# 创建两个数据帧df1和df2
df1 <- data.frame(ID = c(1, 2, 3, 4),
                  Name = c("Alice", "Bob", "Charlie", "David"))

df2 <- data.frame(ID = c(2, 3),
                  Age = c(25, 30))

# 使用left_join()函数将df2中的Age列添加到df1中，根据ID进行匹配
joined_df <- left_join(df1, df2, by = "ID")

# 输出合并后的数据帧
print(joined_df)