Get next true value from a given array index in Julia | Array findnext() Method

The findnext() is an inbuilt function in julia which is used to return the next coming index after or including i of a true element of the specified array A, or returns zero if true value is not found. Here values of index or key start from 1 i.e, for index of 1st element is 1, index of 2nd element is 2 and so on.

Syntax:
findnext(A, i)
or
findnext(predicate::Function, A, i)

Parameters:

• A: Specified array
• i: Specified value
• Predicate Function: Determines whether something is true or false based on the specified arguments

Returns: It returns the next coming index after or including i of a true element of the specified array A, or returns zero if true value is not found.

Example 1:

# Julia program to illustrate
# the use of Array findnext() method

# Finding index of next true value coming
# after or including index 1 from
# the 1D array A
A = [false, true, true, false]
println(findnext(A, 1))

# Finding index of next true value coming
# after or including index (1, 1) from
# the 2D array B of size 2 * 2
B = [false false; true false]
println(findnext(B, CartesianIndex(1, 1)))

# Finding index of next true value coming
# after or including index (1, 2, 1) from
# the 3D array C of size 2 * 2*2
C = cat([false false; true false],
        [false true; true false],
        [true false; true true], dims = 3)
println(findnext(C, CartesianIndex(1, 2, 1)))

Output:

Example 2:

# Julia program to illustrate
# the use of Array findnext() method

# Finding index of next even value coming
# after or including index 1 from
# the 1D array A
A = [1, 2, 5, 6]
println(findnext(iseven, A, 1))

# Finding index of next even value coming
# after or including index (1, 1) from
# the 2D array B of size 2 * 2
B = [3 5; 6 7]
println(findnext(iseven, B, CartesianIndex(1, 1)))

# Finding index of next even value coming
# after or including index (1, 2, 1) from
# the 3D array C of size 2 * 2*2
C = cat([1 2; 3 4], [5 6; 7 8],
        [9 10; 11 12], dims = 3)
println(findnext(iseven, C, CartesianIndex(1, 2, 1)))

Output: