Raghuraman Ramachandran wrote:
guRus I have say a dataframe, d and I wish to do the following: 1) For each row, I want to take one particular value of the row and multiply it by 2. How do I do it. Say the data frame is as below: OPEN HIGH LOW CLOSE 1931.2 1931.2 1931.2 1931.2 0 0 0 999.05 0 0 0 1052.5 0 0 0 987.8 0 0 0 925.6 0 0 0 866 0 0 0 1400.2 0 0 0 754.5 0 0 0 702.6 0 0 0 653.25 0 0 0 348 0 0 0 801 866.55 866.55 866.55 866.55 783.1 783.1 742.25 742.25 575 575 575 575 0 0 0 493 470 470 420 425 355 360 343 360 312.05 312.05 274 280.85 257.35 257.35 197 198.75 182 185.95 137 150.75 120.25 129 90.7 101.25 91.85 91.85 57 66.6
Much easier to give us the ?dput output so we can construct this!
How do I multiply only the close of every row using the 'apply' function? And once multiplied how do I obtain a new table that also contains the new 2*CLOSE column (without cbind?).
Guessing here... but why do you want to use apply? Isn't df$new.col <- df$CLOSE * 2 what you want?
2) Also, how do I run a generic function per row. Say for example I want to calculate the Implied Volatility for each row of this data frame ( using the RMterics package). How do I do that please using the apply function? I am focusing on apply because I like the vectorisation concept in R and I do not want to use a for loop etc.
Simply read ?apply to see examples. Apply works on matrices, not data.frames, so if you give it a data.frame, it will be coerced into a matrix.
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