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Is there a way to type lambda λ on a mac without switching the entire keyboard binding to Greek, as described here: How do you type Theta on a Mac?

19

What is your reason for not wanting to switch the entire keyboard binding to Greek? If your reason was just that switching by the menu is a bit cumbersome, then you could set up a keyboard shortcut instead, for very quick layout switching.

With this, it takes just three keystrokes to type a λ (or any other Greek letter). I frequently need to type isolated Greek letters within a mostly latin-alphabet setting (I’m a mathematician), and I find this setup very convenient

In detail:

  • Add a Greek keyboard layout to your input sources, under System Preferences > Keyboard > Input Sources:

how to add an input source

  • add a keyboard shortcut for switching to the most recently-used layout different from the current one, under System Preferences > Keyboard > Shortcuts > Input Sources. I use Command ⌘+Option ⌥+Space, which doesn’t (iirc) conflict with any system default shortcuts:

how to add keyboard shortcut for switching input source

  • Now you can get a λ by typing ++Space (switch the input layout to Greek); l (actually produce the λ); ++Space (switch back to whatever layout you were typing in before). And, as a bonus, the rest of the Greek alphabet is at your fingertips as well!
  • 3
    Why don't you just use the El Capitan default for this shortcut, Control plus Space? – Tom Gewecke Mar 10 '16 at 19:02
  • @TomGewecke: ah, thanks — I didn’t know that was the El Capitan default! I’ve had this set up since a few OS versions ago, during the period when the default for this conflicted with the default for Spotlight — see e.g. this Mountain Lion support article. I guess now I can change to the new default, and re-train my fingers :-) – PLL Mar 10 '16 at 21:55
  • @TomGewecke Isn't the default Cmd+Space? And Ctrl+Space for spotlight? – zenith Mar 11 '16 at 11:08
  • 1
    @zenith On my machine it was the other way around. Also in iOS 9, when you use a hardware keyboard, the shortcut is now Control plus Space to change language (with no way to modify it). – Tom Gewecke Mar 11 '16 at 13:03
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  1. Press Command ⌘+Control ⌃+Space.
  2. Type lamda into the search bar. Pay attention to type lamda instead of lambda.
  3. Your lamda should be there: picture of the Special Symbols Window

You might ask why it is spelt lamda not lambda.

According to the link provided by MJeffryes:

The use of the spelling lamda derives from ISO 10646. This does not mean that it is more correct than lambda, merely that the spelling without the 'b' is the one used in the formal character names.

Here are two more links provided by Itai Ferber:


Here is a website about Mac keyboard shortcuts: https://support.apple.com/en-us/HT201236.

  • 4
    Any idea why it needs to be misspelled? – Jörg W Mittag Mar 10 '16 at 0:51
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    @JörgWMittag Because that's how it's specified in the Unicode spec: unicode.org/charts/PDF/U0370.pdf (search for LAMDA); it's been that way for a long time, it seems (fileformat.info/info/unicode/version/1.1/index.htm). – Itai Ferber Mar 10 '16 at 1:37
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    @JörgWMittag The modern greek spelling of the letter has no b in it, romanized it is "lamda". I suspect that is why Unicode used it. – Tom Gewecke Mar 10 '16 at 4:24
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    @ItaiFerber Indeed, once an incorrect name has entered Unicode, it is impossible to change it. There are several known misspellings. unicode.org/notes/tn27 – MJeffryes Mar 10 '16 at 15:07
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    It's not misspelt. The letter from the Greek block is "LAMDA" following modern Greek spelling. The character from the mathematical block is spelt "LAMBDA" following mathematical convention (and ancient Greek spelling). Both are correct for their intended use case. – Nicholas Shanks Mar 11 '16 at 12:38
4

I use the Emojis and Symbols menu to plug in characters I can't type via the keyboard. Awkward, but it works. (PS - If you happen to be working in Microsoft Word, it's dead easy - in preferences, enable "Math Autocorrect" outside of math fields, then type \lambda to insert it.)

4

If you will be writing it often, I would recommend going to System Preferences → Keyboard → Text and adding a new replace rule: Replace lambda with λ.

3

If you have access to Vim/gVim (the editor, which seems to go by the MacVim name on Mac), go into INSERT mode, press Ctrl + k followed by * followed by l. A λ character will be produced.

Copy that into the clipboard and you're good to go.

You can do this for other Greek letters too, just replace l with a, b, c, d etc. You can also get upper case versions of those letters by just entering them as... upper case!

That applies to other Vim distributions as well.

3

If you are an owner of Alfred Powerpack (only £17), you can download this workflow to search and type in any symbols quickly. That's what I use whenever I need to quickly type in any unicode symbol on my mac.

Works like this :

works like this :

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Copy the λ character from the original post. Paste it wherever you want it ;)

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Three one keystroke solutions:

  1. Install Ukelele and make option-L produce lambda.

  2. Go to System Preferences > Keyboard > Text and check Correct spelling automatically. Then add a rule to replace the standard output of option-L (which is ¬) with λ.

  3. Use Karabiner to do the same. (A bit more difficult.)

  • 2
    for rule 2: the original must contain 2 letters :( – SuperUberDuper Jan 27 '17 at 12:20

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