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[英]R Dataframe: How to multiply filtered values in a column based on the corresponding value in another column?
[英]How to isolate values in a dataframe based on a vector and multiply it by another column in the same dataframe using R?
我有一個包含多列的數據框
col1|col2|col3|colA|colB|colC|Percent
1 1 1 2 2 2 50
早些時候我對列進行了子集化並創建了一個向量
ColAlphabet<-c("ColA","ColB","ColC")
我想要做的是將 ColAlphabet 乘以百分比,所以最后我有
col1|col2|col3|colA|colB|colC|Percent
1 1 1 1 1 1 50
我們可以用mutate
與across
。 指定用all_of
包裹的感興趣的列並將列乘以“百分比”
library(dplyr)
df2 <- df1 %>%
mutate(across(all_of(ColAlphabet), ~ .* Percent/100))
-輸出
df2
# col1 col2 col3 colA colB colC Percent
#1 1 1 1 1 1 1 50
df1 <- structure(list(col1 = 1L, col2 = 1L, col3 = 1L, colA = 2L, colB = 2L,
colC = 2L, Percent = 50L), class = "data.frame", row.names = c(NA,
-1L))
您可以對列進行子集化,乘以Percent
並將其再次保存在ColAlphabet
。
ColAlphabet<-c("colA","colB","colC")
df[ColAlphabet] <- df[ColAlphabet] * df$Percent/100
df
# col1 col2 col3 colA colB colC Percent
#1 1 1 1 1 1 1 50
我們也可以使用apply()
:
#Vector
ColAlphabet<-c("colA","colB","colC")
#Code
df[,ColAlphabet] <- apply(df[,ColAlphabet],2,function(x) x*df$Percent/100)
輸出:
df
col1 col2 col3 colA colB colC Percent
1 1 1 1 1 1 1 50
使用的一些數據:
#Data
df <- structure(list(col1 = 1L, col2 = 1L, col3 = 1L, colA = 2L, colB = 2L,
colC = 2L, Percent = 50L), class = "data.frame", row.names = c(NA,
-1L))
如果你想直接相乘:
> df <- data.frame(col1 = 1, col2 = 1, col3 = 1, colA = 2, colB = 2, colC = 2, Percent = 50)
> df
col1 col2 col3 colA colB colC Percent
1 1 1 1 2 2 2 50
> df[grep('^c.*[A-Z]$', names(df))] <- df[grep('^c.*[A-Z]$', names(df))] * df$Percent/100
> df
col1 col2 col3 colA colB colC Percent
1 1 1 1 1 1 1 50
>
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