Conditional Insert of Rows
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30-06-2021 - |
Question
I have a unique dataset, a portion of which can be reproduced using:
data <- textConnection("SNP_Pres,Chr_N,BP_A1F,A1_Beta,A2_SE,ForSortSNP,SortOrder
rs122,13,100461219,C,T,rs122,6
1,16362,0.8701,-0.0048,0.0056,rs122,7
1,19509,0.546015137607046,-0.0033,0.0035,rs122,8
1,17218,0.1539,-0.004,0.013,rs122,9
rs142,13,61952115,G,T,rs142,6
1,16387,0.1295,0.0044,0.0057,rs142,7
1,17218,0.8454,0.006,0.013,rs142,9
rs160,13,100950452,C,T,rs160,6
1,16387,0.549,-0.0021,0.0035,rs160,7
1,19509,0.519102731537216,0.003,0.0027,rs160,8
rs298,13,66664221,C,G,rs298,6
1,19509,0.308290808358246,-0.0032,0.0033,rs298,8
1,17218,0.7227,0.022,0.01,rs298,9")
mydata <- read.csv(data, header = T, sep = ",", stringsAsFactors=FALSE)
It is formatted for use in a program that requires holding spots for missing data entries. In this case, a missing entry is indicated by a numeric skip in the Sort Order
column. An entry is complete if the column descends 6 - 7 - 8 - 9, with a new entry beginning again with 6.
I need a way to read through the data file, and insert a row of zeros for each missing entry, so that the file looks like this:
data <- textConnection("SNP_Pres,Chr_N,BP_A1F,A1_Beta,A2_SE,ForSortSNP,SortOrder
rs122,13,100461219,C,T,rs122,6
1,16362,0.8701,-0.0048,0.0056,rs122,7
1,19509,0.546015137607046,-0.0033,0.0035,rs122,8
1,17218,0.1539,-0.004,0.013,rs122,9
rs142,13,61952115,G,T,rs142,6
1,16387,0.1295,0.0044,0.0057,rs142,7
0,0,0,0,0,rs142,8
1,17218,0.8454,0.006,0.013,rs142,9
rs160,13,100950452,C,T,rs160,6
1,16387,0.549,-0.0021,0.0035,rs160,7
1,19509,0.519102731537216,0.003,0.0027,rs160,8
0,0,0,0,0,rs160,9
rs298,13,66664221,C,G,rs298,6
0,0,0,0,0,rs289, 7
1,19509,0.308290808358246,-0.0032,0.0033,rs298,8
1,17218,0.7227,0.022,0.01,rs298,9")
mydata <- read.csv(data, header = T, sep = ",", stringsAsFactors=FALSE)
Ultimately, the last two columns, ForSortSNP
and SortOrder
will be deleted from the data file, but they are included now for convenience's sake.
Any suggestions are greatly appreicated.
La solution
Here is a solution using the expand.grid
and merge
functions.
grid <- with(mydata, expand.grid(ForSortSNP=unique(ForSortSNP), SortOrder=unique(SortOrder)))
complete <- merge(mydata, grid, all=TRUE, sort=FALSE)
complete[is.na(complete)] <- 0 # replace NAs with 0's
complete <- complete[order(complete$ForSortSNP, complete$SortOrder), ] # re-sort