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# Blog

## Black-Scholes Option Pricing in R

The Black-Scholes or Black-Scholes-Merton model is a financial mathematical equation for pricing options contracts and other derivatives. Fischer Black and Myron Scholes published the formula in their 1973 paper "The Pricing of Options and Corporate Liabilities"....

## How to Solve R Error: unexpected ‘}’ in “}”

This error occurs when you have a closing curly bracket in your code without a corresponding opening curly bracket. You can solve this error by finding the position in your code that requires an opening bracket. This tutorial will go through how to solve the error...

## How to Remove Legend in ggplot2

You can remove a legend from a plot using the syntax legend.position="none" for the plot theme. For example, library(ggplot2) ggplot(data = mtcars, aes(x = mpg, y = disp, color = vs)) + geom_point() + theme(legend.position="none") This tutorial will go through how to...

## How to Solve R Error in file(file, ifelse(append, ‘a’, ‘w’)) : cannot open the connection

This error occurs if you try to write to a file in a directory that was not found by the R interpreter. You can solve this error by creating the directory using dir.create() or removing the missing directory from the file save path. For example, x <- c(rnorm(10))...

## How to Center Plot Title in ggplot2 with R

The easiest way to center a title using ggplot2 is to modify the plot.title component of the theme using element_text(hjust=0.5). For example, library(ggplot2) ggplot(data=mtcars, aes(x=mpg, y=wt)) + geom_point() + ggtitle("Automobile Weight vs Miles per Gallon") +...

## How to Transpose a Data Frame in R

The easiest way to transpose a data frame is to use the transpose() function from the data.table library. For example, library(data.table) # get data data("mtcars") # transpose t_mtcars <- transpose(mtcars) # get row and colnames in order colnames(t_mtcars) <-...

## How to Apply a Function to Every Row of a Table in R using dplyr

Using the rowwise function from dplyr in combination with the mutation function, you can apply a function to every row in a table. For example, data %>% rowwise() %>% # a, b, c are column names mutate(sum_val = sum(a, b, c)) This tutorial will go through how to use...

## How to Add an Index column to a Data Frame in R

The easiest way to add a sequence of numbers as an index column is to use the nrow() function, for example, df\$index <- 1:nrow(df) This tutorial will explain how to add a numeric ID column to a data frame with code examples. Table of contentsAdd Index Column to...