Or, unreadable code that you should really turn into helper functions whenever you can.
| logic | |
not a == not b |
both or none |
| numbers | |
| math.min(math.max(x, min), max) | clamp x (upper limit takes precedence) |
x ~= x |
number is NaN |
1/0 |
inf |
-1/0 |
-inf |
math.huge == math.huge-1 |
check if inf is available without dividing by zero |
x % 1 |
fractional part (always positive) |
x % 1 == 0 |
number is integer; math.floor(x) == x |
x - x % 1 |
integer part; but better use math.floor(x) |
x - x % 0.01 |
x floored to two decimal digits |
x - x % n |
closest to x smaller than x multiple of n |
math.modf(x) |
integer part and fractional part |
math.floor(x+.5) |
round |
(x >= 0 and 1 or -1) |
sign |
y0 + (x-x0) * ((y1-y0) / (x1 - x0)) |
linear interpolation |
math.fmod(angle, 2*math.pi) |
normalize an angle |
| tables | |
next(t) == nil |
table is empty |
| strings | |
s:match'^something' |
starts with |
s:match'something$' |
ends with |
s:match'["\'](.-)%1' |
match pairs of single or double quotes |
| i/o | |
f:read(4096, '*l') |
read lines efficiently |