考虑以下数据帧:
df <- data.frame(Industry = c("Agriculture", "Fishery", "Industry"),
Value = c(0,0,0))
我想很容易地将一个值放入数据帧中。比方说,我想要"1"的数字;农业";。当然,在这种情况下,我可以很容易地做到:
df <- data.frame(Industry = c("Agriculture", "Fishery", "Industry"),
Value = c(1,0,0))
但我有一个巨大的数据帧,所以这并不是那么容易做到的。相反,我可以写:
change <- c("Agriculture", 1)
如果是macthing,那么它将更新df。但是我该怎么做呢?我应该可以同时改变多个细胞(例如"农业"one_answers"渔业"(。
dplyr
解决方案:
您可以写下要更新的行业列表,然后在mutate
函数中使用%in%
运算符:
library(dplyr)
df <- data.frame(Industry = c("Agriculture", "Fishery", "Industry"),
Value = c(0,0,0))
list_of_industries <- c("Agriculture","Fishery")
df <- df %>%
mutate(Value = ifelse(Industry %in% list_of_industries,
1,
0))
输出:
Industry Value
1 Agriculture 1
2 Fishery 1
3 Industry 0
您可以尝试
df$Value[df$Industry == "Agriculture"] <- 1
Industry Value
1 Agriculture 1
2 Fishery 0
3 Industry 0
和
df$Value[df$Industry %in% c("Agriculture", "Fishery")] <- 1
Industry Value
1 Agriculture 1
2 Fishery 1
3 Industry 0
使用data.table
方法进行合并和就地更新
library(data.table)
# set df as dt
dt <- data.table(df)
# update table
updt <- fread(text="
Industry,New_Value
Agriculture,1
Fishery,2
")
# temporary merge on Industry column to fetch new value
# and inplace update dt
dt[
updt, on="Industry", # merging
Value := New_Value # inplace update
]
得到
Industry Value
1: Agriculture 1
2: Fishery 2
3: Industry 0