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toupper and tolower

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  1. toupper and tolower

toupper and tolower

toupper() converts a string to all uppercase, and tolower() converts it to all lowercase. Both work element-wise across a vector of strings. They're commonly used for case-insensitive comparisons by normalizing both sides to the same case first.

Note: For case-insensitive comparisons, normalize both strings with tolower() before comparing them with ==.

Example: toupper and tolower

markup 
text <- "Hello World"

cat(toupper(text), "\n")
cat(tolower(text), "\n")
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