Add two values with append

Question

I'm learning how to use this program. I have a vector with values called, for example, X. I need to add one zero after the value 11 in my vector, so I have used the function append:

X<- append(X, 0, after=11)

It works properly, but I have problems when I want to add two zeroes between two different values in the vector. How can I indicate to the function that I want one zero after the values 3 and 11? I have tried with after= c(3,11) and after= (3,11), and it doesn't work.

For now, I have fixed it by writing it again but I'm sure there is a better solution:

X<- append(X, 0, after=3); X<- append(X, 0, after=11)

Thank you and I'm sorry cause my english is not very good

akrun · Accepted Answer · 2019-12-28T20:57:33.643

0

If we are inserting at multiple positions

nvalues <- 2
pos <- c(3, 5, 7)
pos1 <- c(pos[1], seq_along(pos[-1]) * nvalues + pos[-1])
for(i in seq_along(pos)) X <- append(vec, c(0, 0), after = pos1[i])
X
#[1]  3  4  2  0  0  5  3  0  0  9 10  0  0 12 14

It can be wrapped into a function

f1 <- function(vec, nvalues, posvec, value) {
    posvec1 <- c(posvec[1], seq_along(posvec[-1]) * nvalues + 
           posvec[-1])
    for(i in seq_along(posvec)) vec <-  append(vec, 
               rep(value, nvalues), after = posvec1[i])
    vec
 }



f1(X, 1, c(3, 5, 7), 0)
#[1]  3  4  2  0  5  3  0  9 10  0 12 14
f1(X, 2, c(3, 5, 7), 0)
#[1]  3  4  2  0  0  5  3  0  0  9 10  0  0 12 14
f1(X, 3, c(3, 5, 7), 0)
#[1]  3  4  2  0  0  0  5  3  0  0  0  9 10  0  0  0 12 14

data

X <- c(3, 4, 2, 5, 3, 9, 10, 12, 14)

edited Dec 28 '19 at 20:57

answered Dec 28 '19 at 19:47

akrun

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I have explained wrong. 3 is not a value, is the position of one value. I have a lot of values, for example 50, and I need to add a 0 between the 3 and 4 positions – manu Sánchez Dec 28 '19 at 19:51
Thats why I used append(X, 0, after=3), but now i need to add 0s in more places, so I need to know who to indicate in the argument after= that there are more than one position – manu Sánchez Dec 28 '19 at 19:52
@manuSánchez can you pleases update with a good example and expected output – akrun Dec 28 '19 at 19:54
@manuSánchez You can check my updated solution – akrun Dec 28 '19 at 20:07
it doesnt work... im going to try to explain it better wait – manu Sánchez Dec 28 '19 at 20:18
@manuSánchez I showed with a working example – akrun Dec 28 '19 at 20:18
It's like just the same you did but just adding one 0 in different possitions. – manu Sánchez Dec 28 '19 at 20:22
I'm sorry cause I know that I'm annoying, but I have started very recently using this so I'm very lost and frustated hahah I'm so grateful for your help! – manu Sánchez Dec 28 '19 at 20:23
@manuSánchez if you check my example, i am inserting 2 0s after positions 3, 5, and. 7 in the original vector – akrun Dec 28 '19 at 20:24
I don't know how to do the same as you did but just with adding one 0 in different positions – manu Sánchez Dec 28 '19 at 20:24
@manuSánchez If you check my code `nvalues <- 2`, it should be 1 and in the `append`, it would be `0` instead of c(0, 0) – akrun Dec 28 '19 at 20:25
@manuSánchez I updated with a funciton. You can check it – akrun Dec 28 '19 at 20:31

Add two values with append

1 Answers1

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