I have two matrices A and B, where matrix A of order 261*24 and matrix B of order 104*24, I want to merge matrix B in A in such a way that rows of B [1,2,3,4,5,...,104] are merge in following row position in A as [5,6,12,13,19,20,26,27,33,34,40,41,47,48,54,55,61,62,68,69,75,76,82,83,89,90,96,97,....]

so that matrix A becomes of order 365*24. How I could do this in R?

Hi there,

Happy to help if you can make a reprex (FAQ: How to do a minimal reproducible example ( reprex ) for beginners) . Go ahead and make a smaller version of the two matrices as well as the solution will probably be able to generalise for your specific requirement.

thanks, Grey Merchant for your suggestion.

Hi @faheem

I went with the approach to add an index to each row of the two matrices and arrange them according to that index.

```
#create example data
A <- matrix(sample(20:50, 261*24, replace = TRUE), ncol = 24)
B <- matrix(sample(20:50, 104*24, replace = TRUE), ncol = 24)
```

Then convert each matrix to a tibble, add an index column.

```
library(tidyverse)
A_with_index <- A %>% as_tibble() %>%
mutate(
cuttingpoint = row_number() %/% 5,
index = row_number() + 2* cuttingpoint
)
# A tibble: 261 x 11
#> V16 V17 V18 V19 V20 V21 V22 V23 V24 cuttingpoint index
#> <int> <int> <int> <int> <int> <int> <int> <int> <int> <dbl> <dbl>
#> 1 41 50 33 37 49 20 35 38 35 0 1
#> 2 34 32 29 35 43 24 48 49 48 0 2
#> 3 36 35 45 44 35 23 22 48 30 0 3
#> 4 23 41 23 48 42 24 25 41 50 0 4
#> 5 46 22 30 28 47 44 43 49 42 1 7
#> 6 29 28 47 23 46 21 28 39 42 1 8
#> 7 26 50 43 38 31 34 41 32 43 1 9
#> 8 35 36 30 40 35 46 30 24 44 1 10
#> 9 48 29 36 41 34 39 48 23 47 1 11
#> 10 28 36 29 28 41 37 40 26 21 2 14
#> 11 39 28 50 50 31 50 20 38 30 2 15
B_with_index <- B %>% as_tibble() %>%
mutate(
cuttingpoint = row_number() %/% 2 %>% lag(default = 0),
index = row_number() + 5 * cuttingpoint + 4
)
# A tibble: 104 x 11
#> V16 V17 V18 V19 V20 V21 V22 V23 V24 cuttingpoint index
#> <int> <int> <int> <int> <int> <int> <int> <int> <int> <dbl> <dbl>
#> 1 30 40 20 43 38 38 34 32 27 0 5
#> 2 23 29 20 40 46 33 47 46 34 0 6
#> 3 40 30 29 30 30 36 33 40 48 1 12
#> 4 40 23 31 23 34 22 31 47 26 1 13
#> 5 28 47 36 36 40 49 22 49 44 2 19
#> 6 34 37 27 41 31 27 43 28 28 2 20
#> 7 39 20 48 25 46 37 36 34 22 3 26
```

And then your result, back to a matrix:

`A_plus_B <- bind_rows(A_with_index, B_with_index) %>% arrange(index) %>% select(-cuttingpoint, -index) %>% as.matrix()`

Hope it helps.

yes it help but I do this in a very simple way

```
A<- matrix(2:21, nrow = 40, ncol=4)
B <- matrix(2*(1:32),nrow = 8, ncol=4)
R <- matrix(0, nrow(A) + nrow(B), ncol(A))
i <- 5:6 + rep(7L * 0:(nrow(B)/2-1), each = 2L)
R[i, ] <- B
R[-i, ] <- A
```

I think this more simple

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