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Comment by todd8 | Hacker News Reader

In the past when I needed a calculator on someone’s Mac, I just started Python in a terminal and typed in expressions to be evaluated. It was nice to be able to find it on any Mac and it’s much nicer to type into Python’s REPL than clicking on a calculator’s GUI buttons. Now, Windows machines will have Python and Macs may not.

On Macs and Linux I can still use the bc command instead (it’s an old Unix command) but it’s far less handy than Python. See the bc man page.

There’s also dc, the even less used, reverse Polish notation calculator. It is a standard Unix command that predates bc.

Interestingly, the dc “language” is older than C, Awk, Perl, or any other programming language still found on Unix systems. It is implemented in C’s predecessor, the language B.

You can tell that bc and dc are early Unix commands from their names, many of the oldest Unix commands are just two characters long.

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FWIW, macOS has Spotlight Search and it works as a calculator as well. (⌘+SPACE to activate it).

I use spotlight a lot, but never for calculations. I’ll have to try that out.

The ability to use variables, math functions, lists, loops, and completion in Python will likely keep me using it as my basic calculator. Although I need to figure out a way to edit my REPL history to fix typos better.

>In the past when I needed a calculator on someone’s Mac, I just started Python in a terminal and typed in expressions to be evaluated (...) The ability to use variables, math functions, lists, loops, and completion in Python will likely keep me using it as my basic calculator.

Why do you do math on random people's laptops?

Tech support for family, friends, coworkers.

I do all that too, it rarely, if ever, involves math. Installing this, formatting that, removing some virus, installing some hardware, configuring the OS or a program yes.

Yes, a lot of the tech support falls into your enumeration, but I was Chief Scientist at a company for over six years, an OS Architect at IBM for five years and subsequently have done years of part time consulting at a number of startups. It's not unusual to be in someone's office or even having coffee with my daughter (she studying engineering) when some question that involves simple calculations comes up, things like "Is this algorithm warranted given the data set size?". One of my degrees is in math and perhaps this leads me to think quantitatively about many questions.

In my own office I use perhaps a dozen machines. Servers running FreeBSD, OpenBSD, or Linux. Linux, Windows, and Mac desktops and laptops. Few are actually set up as Python development machines (those of course have recent Python installed), but having a ubiquitous tool for simple calculations (or even short scripts) is quite handy on all of the others.

My work might not be typical: I have been programming for over half a century and I started making use of Python for simple programs in the Python 1.2 time frame around 20 years ago. I'm not really a Python developer, but I appreciate it as a useful tool--even as a keyboard driven calculator.

What completion? The stock REPL doesn’t have that.

I was referring to readline-style completion (as in GNU Readline) as is also found in the bash shell. You're right that the stock REPL doesn't have IDE style completion.

I always use bc -l, as it gives more digits in the reply.

Also available on macs/linux and most unixes. e.g.:

$echo '1/2' | bc

$ echo '1/2' | bc -l

.50000000000000000000

though honestlyI usually just type bc -l you enter into an interactive calculator similar to python.

I do this on the js console in the browser

What's sad is that JavaScript isn't a very convenient language for this type of thing, but it's available (Math.pow(x, y) instead of x \\ y, limited integer accuracy, etc). I usually use the Python REPL, but occasionally I use the browser, it's just so ubiquitous.

I like how this is also your bio (about)!

It's not actually on Windows default installs though, it's just more easily installable. So not much help in your situation. Google will do arithmetic for you, that's often the quickest.

For me on Windows that quick command-line calculator has been PowerShell for a while.

Or bash, just $((1+1)).

This is presumably integer calculation only?

Wait, how do they build dc? Is there a B compiler for 64-bit systems?

Assuming it's OpenBSD or GNU dc, it appears to be written in C.

I wondered that myself, but I've never investigated!

dc has been my preferred calculator forever. I think I tried to use bc but couldn't figure out the syntax, whereas dc was very clear.

Python3 will still be available

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