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# Check if all Elements in Array are Equal in Julia

To check if all elements in an array are equal in Julia, you can use the `all` function along with the `==` operator. The `all` function takes a function or lambda as its first argument, and an array as its second argument. It applies the function to each element of the array and returns `true` if the function returns `true` for all elements in the array, and `false` otherwise.

## Check if all Elements in Array are Equal in Julia Examples

Here is an example that uses the `all` function to check if all elements in an array are equal:

```julia> a = [1, 1, 1, 1]
4-element Array{Int64,1}:
1
1
1
1

julia> all(x -> x == 1, a)
true

julia> b = [1, 2, 3, 4]
4-element Array{Int64,1}:
1
2
3
4

julia> all(x -> x == 1, b)
false```

In the first example, we create an array `a` containing only the value `1`. We then use the `all` function to apply the function `x -> x == 1` to each element of the array. Since this function returns `true` for all elements of the array, the `all` function returns `true`.

In the second example, we create an array `b` containing a range of different values. When we apply the `all` function to this array, it returns `false` because not all elements of the array are equal to `1`.

You can also use the `==` operator directly with the `all` function, as shown in this example:

```julia> a = [1, 1, 1, 1]
4-element Array{Int64,1}:
1
1
1
1

julia> all(a .== 1)
true

julia> b = [1, 2, 3, 4]
4-element Array{Int64,1}:
1
2
3
4

julia> all(b .== 1)
false```

In this example, we use the `all` function to apply the `==` operator to each element of the array. This is equivalent to the previous example, but it uses a more concise syntax.

Overall, the `all` function is a simple and effective way to check if all elements in an array are equal in Julia.

Here is an advanced example that demonstrates some additional features of the `all` function:

```julia> a = [1, 2, 3, 4]
4-element Array{Int64,1}:
1
2
3
4

julia> # Check if all elements of the array are odd numbers
julia> all(x -> isodd(x), a)
false

julia> # Check if all elements of the array are greater than 0
julia> all(x -> x > 0, a)
true

julia> # Check if all elements of the array are less than or equal to 3
julia> all(x -> x <= 3, a)
false

julia> # Check if all elements of the array are integers
julia> all(x -> isinteger(x), a)
true```

In the above example, we use the `all` function to apply different functions to the elements of the array. We first check if all elements of the array are odd numbers using the `isodd` function. Then we check if all elements of the array are greater than 0 using the `x > 0` lambda. Next, we check if all elements of the array are less than or equal to 3 using the `x <= 3` lambda. Finally, we check if all elements of the array are integers using the `isinteger` function.

This example demonstrates how the `all` function can be used to check a wide variety of properties of the elements in an array. It can be a useful tool for working with arrays in Julia.