How to add last element of vector to next vector

Consider a vector A= [1 2 3 4 5] and another vector B=[ 10 11 17 22 24]

Now what i want to do is that last element of A i.e. A(end) which in this case is 5 shall be added to the first element of B i.e. B(1 ) which in this case is 10. The result which is 15 shall be placed in any other vector or in A as A=[ 1 2 3 4 5 15]. Uptill now its easy. Now the difficult part where I am stuck. the difference of successive elements after neglecting first element of B is any vector C= [ 6 5 2].

Now I want to form a vector D (or the same vector A can be modified) in the following form [1 2 3 4 5 15 21 26 28] i.e. last element of A is added with the first element of C and is given a position in A at the end. Again this newly added number is placed at the end of A and is added with C(2) element i.e. 5 and added at the end position of A and so on.

Can any one please help?

Answer 1

[Ameer Hamza]

Try this

A = [1 2 3 4 5];
B = [ 10 11 17 22 24];

D = [A A(end)+B(1)];
D = [D cumsum(diff(B(2:end)))+D(end)];

[Muhammad Ali Khan]

Thank you very much Ameer Hamza for the help. Its working perfectly fine.

But I need a bit more help as I am using for loop. After each iteration, the value of B changes. What I want is that instead of overwriting D with new values, it shall also add to D.

The code you advised gives the following result:

D = 1 2 3 4 5 15 21 26 28

Now lets say the value of B for three iterations are vector B1 =[ 27 29 33], B2 =[ 52 60 64] and B3 = [ 70 73, 81].

now after execution of complete loop, the D shall be in the following format.

D=[1 2 3 4 5 15 21 26 28 55 57 61 113 121 125 195 198 206 ]

Please guide

[NAVNEET NAYAN]

Were you looking for D = [1 2 3 4 5 15 21 26 28] or D=[1 2 3 4 5 15 21 26 28 33 35 37] ? Because as per your question after 28, 5 needs to be added to 28 giving 33 and then 2 should be added to 33 to give 35 and finally after adding last element 2 to 35 should give 37. Please correct me, if I am interpretting your question wrongly.

[Muhammad Ali Khan]

@NAVNEET Nayan

D=[1 2 3 4 5 15 21 26 28 55 57 61 113 121 125 195 198 206 ]

The first five elements of D are obtained from vector A i.e. A= [1 2 3 4 5]

after meeting some condition in a loop, I attained a vector B=[ 10 11 17 22 24]. Now D is such that D= [ 1 2 3 4 5 15] where 15 i.e.e last element of D is attained by adding last element of A with first element of B. (5 +10=15).

Further elements in D are obtained by subtracting each element of B with its succsessive element i.e. [6 5 2] and adding it with the current end elemnt of D.

Hence D now becomes D = [1 2 3 4 5 15 21 26 28].

Now again the iteration for loop begins for lets say three more times. For each iteration I attain the follwing

B1 =[ 27 29 33], B2 =[ 52 60 64] and B3 = [ 70 73, 81]

Repeating the above procedure for each B, i.e. adding its first element to the last of element of D placing the result as last emlement of D. the difference of successive elements of B's are added to tht last element of D.

In this case D becomes

D=[1 2 3 4 5 15 21 26 28 55(28+27) 57(55+(29-27)) 61(57+(33-29)) 113(61+52) 121 (113-(60+-52)) 125 195 198 206 ]

please let me know if I am vague.

Thanks

[NAVNEET NAYAN]

Got it now. No you are not vague. I was not knowing the entire scenario.