A fifth strategy for writing clean R code is to use vectorization and apply functions to optimize your code and improve its performance. Vectorization is the process of applying an operation to a vector or a matrix, rather than to each element individually. Vectorization can make your code faster and more efficient, as R is optimized for vector operations. You can use vectorized functions, such as arithmetic operators, logical operators, or string functions, to perform vectorized operations. For example, instead of using a loop to add 1 to each element of a vector, you can use a vectorized operation like vector + 1. Apply functions are a family of functions that allow you to apply a function to a subset of a data object, such as a row, a column, or a list. Apply functions can help you avoid loops and simplify your code. You can use different apply functions depending on the type and dimension of your data object, such as apply, lapply, sapply, or tapply.