deltas

Syntax

deltas(X, [n])

Arguments

X is a scalar/vector/matrix/table.

n (optional) is an integer specifying the step to shift when comparing the current element to another element in X. For each element X_i in X, return X_i-X_i-n. The default value is 1, meaning to subtract the current element by the adjacent element at right, i.e., X_i-X_i-1.

Details

If X is a vector, return a vector containing the subtractions between two elements.
If X is a matrix, conduct the aforementioned calculation within each column of X. The result is a matrix with the same shape as X.
If X is a table, conduct the aforementioned calculation within each column of X. The result is a table with the same shape as X.

Examples

x=7 4 5 8 9;
deltas(x);
// output: [,-3,1,3,1] 

x=NULL 1 2 NULL 3;
deltas(x);
// output: [,,1,,]

m=matrix(1 3 2 5 6, 0 8 NULL 7 6);
m;


#0	#1
1	0
3	8
2
5	7
6	6

deltas(m);


#0	#1

2	8
-1
3
1	-1

When n is a positive integer:

m=matrix(1 3 2 5 6, 0 8 NULL 7 6);
a=deltas(m,2)
a;


0	1


1
2	-1
4

When n is a negative integer:

m = 3 4 6 9
r2= deltas(m,-2)
r2; // output: [-3,-5,,]