nushell/docs/commands/math-eval.md
Shaurya Shubham ffe3e2c16b
Rename calc to math eval and allow it to optionally take an expression as an argument (#2195)
* Rename `calc` to `math eval` and allow it to optionally take the expression as an argument

* Moved calc tests to math eval
Also added 2 tests and changed 1 test

* Move calc docs to math eval
2020-07-18 16:11:19 +12:00

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# math eval
math eval is a command that takes a math expression from the pipeline and evaluates that into a number. It also optionally takes the math expression as an argument.
This command supports the following operations -
operations:
* binary operators: +, -, *, /, % (remainder), ^ (power)
* unary operators: +, -, ! (factorial)
functions:
* sqrt, abs
* exp, ln, log10
* sin, cos, tan, asin, acos, atan, atan2
* sinh, cosh, tanh, asinh, acosh, atanh
* floor, ceil, round
* signum
* max(x, ...), min(x, ...): maximum and minimum of 1 or more numbers
constants:
* pi
* e
## Examples
```shell
> echo "1+2+3" | math eval
6.0u
```
```shell
> echo "1-2+3" | math eval
2.0
```
```shell
> echo "-(-23)" | math eval
23.0
```
```shell
> echo "5^2" | math eval
25.0
```
```shell
> echo "5^3" | math eval
125.0
```
```shell
> echo "min(5,4,3,2,1,0,-100,45)" | math eval
-100.0
```
```shell
> echo "max(5,4,3,2,1,0,-100,45)" | math eval
45.0
```
```shell
> echo sqrt(2) | math eval
1.414213562373095
```
```shell
> echo pi | math eval
3.141592653589793
```
```shell
> echo e | math eval
2.718281828459045
```
```shell
> echo "sin(pi / 2)" | math eval
1.0
```
```shell
> echo "floor(5999/1000)" | math eval
5.0
```
```shell
> open abc.json
───┬──────
# │ size
───┼──────
0816
11627
21436
31573
4935
552
6999
71639
───┴──────
```
```shell
> open abc.json | format "({size} + 500) * 4"
───┬──────────────────
# │
───┼──────────────────
0(816 + 500) * 4
1(1627 + 500) * 4
2(1436 + 500) * 4
3(1573 + 500) * 4
4(935 + 500) * 4
5(52 + 500) * 4
6(999 + 500) * 4
7(1639 + 500) * 4
───┴──────────────────
```
```shell
> open abc.json | format "({size} + 500) * 4" | math eval
───┬───────────
# │
───┼───────────
0 │ 5264.0000
1 │ 8508.0000
2 │ 7744.0000
3 │ 8292.0000
4 │ 5740.0000
5 │ 2208.0000
6 │ 5996.0000
7 │ 8556.0000
───┴───────────
```
```shell
> open abc.json | format "({size} - 1000) * 4" | math eval
───┬────────────
# │
───┼────────────
0 │ -736.0000
1 │ 2508.0000
2 │ 1744.0000
3 │ 2292.0000
4 │ -260.0000
5 │ -3792.0000
6 │ -4.0000
7 │ 2556.0000
───┴────────────
```
Note that since `math eval` uses floating-point numbers, the result may not always be precise.
```shell
> echo "floor(5999999999999999999/1000000000000000000)" | math eval
6.0
```