CODEWITHSUNDEEP
rdataframevector
Esteban Julio Ricardo
Esteban Julio Ricardo

Reputation: 1

How do I add a column with a different number of rows?

I am calculating returns in R, and trying to add it to the current dataframe I am working with, but it doesnt work due to a difference in rows, where as existing rows are 194, and assigned data has 193 rows.

This code works just fine when doing it on its own:

diff(log(capm$price_Ford))

But when I try to assign it into the dataframe as its own column, I get the an error

capm$ford_ret <- diff(log(capm$price_Ford))

How can I assign the data with 193 rows, to a dataframe with 194 rows?

Upvotes: 0

Views: 274

Answers (1)

Konrad Rudolph
Konrad Rudolph

Reputation: 545588

How can I assign the data with 193 rows, to a dataframe with 194 rows?

In a nutshell, you can’t. Each column in a table must have the same number of rows. You need to decide what to fill into the row that’s missing a value. Depending on your use-case, this might for example be 0 or NA. You also need to decide whether the missing value should go at the beginning or at the end (for a difference, usually at the beginning). For example:

capm$ford_ret <- c(NA, diff(log(capm$price_Ford)))

Upvotes: 2

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