![]() ![]() Suppose you want to do several printouts of the following form: The year is where is equal to 2010, 2011, up to 2015. With RMarkdown you can write Markdown syntax in an (Rmd) file, interspersed with code blocks with R code. Knitr reads the R-code, executes it in R and pastes the results back into the markdown output. Let’s do this in R First, we have to specify a data object that we can use within the for-loop: xfor <- 0 Preliminary specification of data object. The trick to looping over a set of data and. xfor <- 0 Preliminary specification of data object. Our exemplifying data object is simply containing the numeric value 0. ![]() You can do this as follows: print(paste("The year is", 2010)) Let’s assume that we want to run a for-loop that iterates over a. There is a for loop construction in R which has form > for (name in expr1) expr2where name is the loop variable.expr1 is a vector expression, (often a sequence like 1:20), and expr2 is often a grouped expression with its sub-expressions written in terms of the dummy name.expr2 is repeatedly evaluated as name ranges through the values in the vector result of expr1. You immediately see this is rather tedious: you repeat the same code chunk over and over. This violates the DRY principle, known in every programming language: Don’t Repeat Yourself, at all cost.In programming, loops are used to repeat a block of code as long as the specified condition is satisfied. Loops help you to save time, avoid repeatable blocks of code, and write cleaner code. While loops are used when you don't know the exact number of times a block of code is to be repeated.
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