将数据框中的列包含在R中的另一列中

Question

This is my matrix. I want to include columns from other matrix in this matrix bellow:

first.matrix<-structure(list(Datas = structure(c(18131, 18130, 18129, 18128, 
18127), class = "Date"), `A~B` = c(-1.92963017062521, -3.59752795018039, 
-3.72377538845192, -2.33607407809712, -2.98577937429645), `2x` = c(2.96383224677759, 
2.96383224677759, 2.96383224677759, 2.96383224677759, 2.96383224677759
), `-2x` = c(-2.96383224677759, -2.96383224677759, -2.96383224677759, 
-2.96383224677759, -2.96383224677759), Take = c("Acima/Entre SD", 
"Acima/Entre SD", "Entrada", "Acima/Entre SD", "Acima/Entre SD"
)), row.names = c("1", "2", "3", "4", "5"), class = "data.frame")

The other matrix is this one:

second.matrix<-structure(list(A = c(34, 33.4, 35.18, 35.4, 34.9), B = c(47.87, 
48.94, 50.85, 49.68, 49.83), C = c(49.68, 49.98, 49.99, 48.79, 
47.74), D = c(49.65, 46.1, 44.9, 44.92, 44.75)), class = "data.frame", row.names = c(NA, 
5L))

This is what I need: As you can see the first matrix has a column like this A~B . So, the code should go to the second.matrix Identifies the column before and after the ~ , extract it and include in the first matrix.

Any help guys?

PS: In my real code the first.matrix matrix are in a list of matrix. But if you help me with this code I believe I will be able to extend to my real code.

Many thanks guys

Answer 1

If first.matrix always includes ~ for indicating the merging of the columns,

# To find the index of the columns including ~ inside,

index <- strsplit(names(first.matrix)[grepl("~",names(first.matrix))],"~")

# cbind wrt the index

lapply(seq(index),function(i) cbind(first.matrix,second.matrix[,index[[i]]]))

gives,

[[1]]
       Datas       A~B       2x       -2x           Take     A     B
1 2019-08-23 -1.929630 2.963832 -2.963832 Acima/Entre SD 34.00 47.87
2 2019-08-22 -3.597528 2.963832 -2.963832 Acima/Entre SD 33.40 48.94
3 2019-08-21 -3.723775 2.963832 -2.963832        Entrada 35.18 50.85
4 2019-08-20 -2.336074 2.963832 -2.963832 Acima/Entre SD 35.40 49.68
5 2019-08-19 -2.985779 2.963832 -2.963832 Acima/Entre SD 34.90 49.83

Answer 2

If you want to keep the colnames' A and B`

New_df <- cbind(first.matrix, A = second.matrix$A, B = second.matrix$B)

# Datas       A~B       2x       -2x           Take     A     B
# 1 2019-08-23 -1.929630 2.963832 -2.963832 Acima/Entre SD 34.00 47.87
# 2 2019-08-22 -3.597528 2.963832 -2.963832 Acima/Entre SD 33.40 48.94
# 3 2019-08-21 -3.723775 2.963832 -2.963832        Entrada 35.18 50.85
# 4 2019-08-20 -2.336074 2.963832 -2.963832 Acima/Entre SD 35.40 49.68
# 5 2019-08-19 -2.985779 2.963832 -2.963832 Acima/Entre SD 34.90 49.83