CODEWITHSUNDEEP
rdataframegroupingrowsseq
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Reputation: 185

Group rows within a data.frame based on specific sequence of grouping numbers

Here an example of my data.frame:

df = read.table(text = 'colA
1
1
1
0
1
1
0
0
0
1', header = TRUE)

I need to group colA rows based on specific grouping numbers, such as 3, 2, 2, 3 and assign to them a number from 1900 to 1903.

Desired output:

 colA  colB
    1   1900
    1   1900
    1   1900
    0   1901
    1   1901
    1   1902
    0   1902
    0   1903
    0   1903
    1   1903

The 4 grouping numbers mean: 1st group = first 3 rows, 2nd group = subsequent 2 rows, 3rd group = subsequent 2 rows and 4th group = subsequent 3 rows.

Any suggestion?

Upvotes: 2

Views: 77

Answers (1)

akrun
akrun

Reputation: 886938

We can just use rep

df$colB <- rep(1900:1903, c(3, 2, 2, 3))
df$colB
#[1] 1900 1900 1900 1901 1901 1902 1902 1903 1903 1903

Upvotes: 1

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