Find and replace with regular expressions in Write by Zaweba

Finding a word is easy in any editor. Finding every phone number, every date written the American way, or every double space after a full stop is harder, and that is where the options in Write by Zaweba's Find and Replace earn their keep.

The basic options

Find and Replace looks for text and, if you want, swaps it for something else. Two ticks make plain searches more precise.

Match case looks only for text with the same capitals. Searching for "May" with Match case finds the month and ignores the word "may" in the middle of a sentence.

Whole word ignores matches inside longer words. Searching for "art" as a whole word finds "art" but not "start" or "party". Without it, a replace can wreck words you never meant to touch.

Use both freely. Most bad replacements happen because a search was looser than intended.

Regular expressions

The third tick turns on regular expressions. A regular expression is a pattern that describes text rather than spelling it out. Instead of searching for one phone number, you describe what a phone number looks like.

A few building blocks go a long way. A backslash followed by d stands for any digit. A full stop stands for any single character. A plus sign means one or more of the thing before it. Square brackets hold a set of characters, any one of which can match.

With those, you can find every run of two or more spaces, every number in a document, or every word that starts with a capital letter. You can see each match before deciding whether to replace.

Groups and $1 in the replacement

Parts of a pattern can be wrapped in round brackets to make a group. In the replacement, $1 stands for whatever the first group matched, $2 for the second, and so on.

That lets you rearrange text rather than just swap it. Say a list has names written as surname, comma, first name, and you want first name then surname. A pattern with one group for the surname and one for the first name, and a replacement of $2 followed by a space and $1, flips every name in one go.

The same idea works on dates. If a document has dates in month, day, year order separated by slashes, groups let you swap the month and day so they read the British way.

Mistakes are reported, not fatal

Regular expressions are easy to get slightly wrong. A missing bracket or a stray symbol makes a pattern invalid. Write reports a broken pattern rather than crashing, so you can fix it and try again without losing your work.

Working safely

Test the pattern with Find before you Replace. Step through a few matches and make sure each is what you meant.

Replace a few at a time on anything important. When you are sure, replace all.

Keep undo in mind. A replace all that went wrong can be undone, and undo in Write is unlimited, so you can go back even after a few more edits.

Save a copy first when a document is long or precious. A regular expression replace touching hundreds of places is quick, and so is the damage if the pattern was wrong.

Plain find and replace covers most everyday jobs. Regular expressions are for the bigger clean-ups: tidying a list exported from another system, fixing a consistent typing habit across a long report, or reshaping data before you convert it into a table.