deltas

Syntax

deltas(X, [n])

Details

For each element X_i in X, return X_i-X_i-n, representing the differences between elements.

Parameters

X is a vector, matrix or table.

n (optional) is an integer specifying the step to shift when comparing elements in X. The default value is 1, meaning to compare the current element with the adjacent element at left.

Returns

A vector/matrix/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,,]