# sign

sign(x)

Return zero if `x==0` and \$x/|x|\$ otherwise (i.e., Â±1 for real `x`).

## Examples

In the Julia programming language, the function `sign(x)` returns zero if `x` is equal to zero, and `x/|x|` otherwise. It essentially returns ±1 for real `x`. Here are some examples of its usage:

1. Determine the sign of a number:

``````julia> sign(5)
1

julia> sign(-3)
-1``````

This example shows how the `sign` function returns `1` for positive numbers and `-1` for negative numbers.

2. Handle zero input:

``````julia> sign(0)
0``````

When the input is zero, the `sign` function returns `0`.

3. Compute the sign of an array:

``````julia> arr = [-2, 4, -6, 8];
julia> sign.(arr)
4-element Array{Int64,1}:
-1
1
-1
1``````

By using the dot syntax (`.`), we can apply the `sign` function element-wise to an array.

Common mistake example:

``````julia> sign("Hello")
ERROR: MethodError: no method matching sign(::String)``````

In this example, the `sign` function is applied to a string, which is not a valid argument. The `sign` function is only applicable to numeric types. Make sure to pass appropriate numeric values to the `sign` function to avoid such errors.