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Exercise

Replacing with regular expressions

Now, you've mastered matching with backreferences, you'll build up to replacing with backreferences, but first let's review str_replace() now that you've got regular expressions under your belt.

Remember str_replace() takes three arguments, string a vector of strings to do the replacements in, pattern that identifies the parts of strings to replace and replacement the thing to use as a replacement.

replacement can be a vector, the same length as string, each element specifies the replacement to be used in each string. Let's practice by anonymizing some of the contact objects you've seen so far.

Instructions
100 XP

Text containing phone numbers has been pre-defined in a variable named contact.

  • Replace a digit in contact with "X" using str_replace().
  • Replace all digits in contact with "X" using str_replace_all(). (str_replace() will only replace the first match to the pattern. str_replace_all() will replace all matches to the pattern.)
  • Replace all digits in contact using str_replace_all(), but now specify the vector c("X", ".", "*", "_") as replacement. Notice how now each string uses a different replacement character.