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How to type square brackets ([)

Also called brackets, box brackets, crotchets.

Press the key to the right of P with your right little finger for [, and the key beside it for ]. No Shift — adding Shift gives curly brackets instead.

Which finger types [

Finger
Right pinky
Resting position
; on the home row
Shift
Not required
Hand
right

No website can detect which finger you actually used — a browser reports the character, not the hand that produced it. The finger above is the one the standard touch typing layout assigns, and it is the one the lessons here train.

What [ is used for

  • Index into a list or array in nearly every programming language.
  • Enclose an array in JSON.
  • Define a character set in a regular expression.
  • Mark an editorial insertion inside a quotation.

Where it comes from

Printers called them crotchets and used them for a writer's own interpolation into someone else's text — words that belonged to the editor rather than the author. That is still the rule in careful prose, and it is close to how programming uses them: something inserted into a structure from outside.

The mistake people make

Reaching for them with the ring finger. Both belong to the right little finger, which already handles Enter, the quote and the semicolon. Under speed the finger tends to hit the wrong one of the pair, which is why bracket mismatches cluster in fast typing rather than slow.

If the key is missing or gives the wrong character

  • Windows: Alt+91 for [ and Alt+93 for ] on the numeric keypad.

Practise it properly

Knowing which finger owns a key is not the same as using it without thinking. The Typometer course blocks on the wrong key and names the finger for every one, so the habit forms rather than the knowledge.

Other keys

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