Question

I would like to transform/modify the content of dataframe. Basically I have a dataframe like below:

        bins      pval
1   2L:1:150 0.9224217
2 2L:151:300 0.9478824
3 2L:301:450 0.9671139
4 2L:451:600 0.9280847
5 2L:601:750 0.9698584
6 2L:751:900 0.9725379

And I would like to transform/modify into another dataframe like this, where I split the content of my “bins” column (first row) into 150 rows containing the same values. And so on for the second row.

    chr  pos    pval
1   2L   1 0.9224217
2   2L   2 0.9224217
3   2L   3 0.9224217
4   2L   4 0.9224217
5   2L   5 0.9224217
...
150  2L   150 0.9224217
151  2L   151 0.9478824
152  2L   152 0.9478824
153  2L   153 0.9478824
etc...

Any help much appreciated,

Ben

Answer 1

The quick answer which may be, I fear, too specific and may need generalization. Assume the first dataframe is named “df1”:

data.frame(chr=”2L”, pos=1:(150*NROW(df1)), pval=rep(df1$pval, each=150) )

Argument recycling should make the “chr” long enough without a rep function.

Edit in reply to comment. If the repeat length is always 150 then the fix is easy:

data.frame(chr = rep(substr(df1$bins, 1,2), each=150), 
           pos = 1:(150*NROW(df1)), 
           pval = rep(df1$pval, each=150) )