Sum only numerical columns and divide values by total

Question

I am having trouble with some calculations on a data frame.

Here is my DF (with many more rows and columns)

What I am trying to do is:

Step (1) - For e

Answer 1

Probably a lot less concise then Ronak's answer, but demonstrates the sweep functionality.

Construct example df:

df <- data.frame(cbind(Firm = c("A", "B", "C", "D"),
                       Assets_Jan_2018 = as.numeric(c(210234, 123144, 897897, 235467)),
                       Assets_Feb_2018 = as.numeric(c(235425, 127124, 789798, 897342)),
                       Returns_Jan_2018 = as.double(c(4.5,  5.3,  1.4, 9.7)),
                       Returns_Feb_2019 = as.double(c(6.7, 1.2, 6.2, 3.2))))

Ensure numeric data types:

df <- type.convert(df)

Calculate the weighted returns:

FirmWeightedReturns <- cbind(Firm = df$Firm,
                             sweep(df[sapply(df, is.numeric) & !(grepl("returns", tolower(colnames(df))))],
                                   2,
                                   as.numeric(sapply(df[sapply(df, is.numeric) & !(grepl("returns", tolower(colnames(df))))], sum)), '/')
                                  * df[grepl("returns", tolower(colnames(df)))])

Summarise as a df:

TotalReturns <- data.frame(lapply(FirmWeightedReturns[sapply(FirmWeightedReturns, is.numeric)], sum))

Output to console:

TotalReturns