Here is how to define and use a calculator, using embedded Python.

These two lines go in your vimrc:

:command! -nargs=+ Calc :py print <args>
:py from math import *

Now use it inside Vim:

:Calc 2**10+5,2**16,2**128
1029 65536 340282366920938463463374607431768211456
:Calc sin(pi/2), log(10)
1.0 2.302585

You have to have Vim compiled with Python support, and have Python on your machine†. Use :version to see which features are included in your Vim.

If you don't have Python support in your Vim, but do have a python command, use this instead

command! -nargs=+ Calc :!python -c "from math import *; print <args>"

You also get complex numbers and other goodies. Google for Python and math. Here is an example from complex math:

:py from cmath import *
:Calc exp(pi*1j) , " Euler famous identify e^i.pi = -1"
(-1+1.22460635382e-016j)

:Calc sum(range(1,100+1)), "Gauss' famous identity sum(1,100)"
5050

ReferencesEdit

• http://docs.python.org/lib/module-cmath.html
• http://mathworld.wolfram.com/EulerFormula.html

dllEdit

These days, Vim Python support in Windows is usually via a dll, installed separately from Vim: :version shows +python/dyn. Go to http://python.org/ to get the Python installer.

To check whether you have Python software that Vim can use (either statically linked or dynamically findable), do :echo has('python') — 0 (zero) means "no", anything else (normally 1) means "yes".

CommentsEdit

If your Vim (7.2 or later) is compiled with +float, you can do scientific calculations in Vim even without Python.

• Use the numeric operators (except %) and floating point functions defined by Vim, see
  • :help expr5
  • :help expr6
  • :help expr7
  • :help function-list and scroll down to Floating point computation
• Exponentiation is pow(base,exponent), not **
• :echo gives you 6-digit precision by default, use printf() for user-specified precision, up to about 15 significant digits on an Intel PC (I don't know how many on a Mac PPC or an an IBM System-z).
• If you can lay hands on (or compile) a Vim patched with Bill McCarthy's additional floating-point functions (#7 in the list), you won't need to know trigonometric formulas for "missing" functions such as tan(), asin(), atan2() etc., and you'll be able to use acos(-1) rather than 4*atan(1) for π, exp(1) rather than a literal value for e.

— Tonymec 03:27, May 5, 2010 (UTC)

• These extra floating point functions will be part of Vim 7.3. They were included in the pre-release on May 21, 2010. JamesVega 18:53, May 21, 2010 (UTC)