R - 在非空行之间的空行中顺序生成数字

Question

If I have a data frame defined as such:

     X      Condition
NA            One
0.169358185   NA
0.94108908    NA
0.772270715   NA
0.809542856   NA
0.426230376   NA
0.54298465    NA
0.386102588   NA
0.147564719   NA
NA            Two
0.083204676   NA
0.030533656   NA
0.905891284   NA
NA            One
0.30843373    NA
0.417785805   NA
0.063145741   NA
0.328035986   NA
NA            Two
0.045242478   NA
0.64039683    NA
0.301090671   NA
0.127325708   NA

And I'd like to sequentially produce numbers between the non-NA values in the Condition column to ultimately end up with a data frame like this:

     X      Condition
NA            One
0.169358185   1
0.94108908    2
0.772270715   3
0.809542856   4
0.426230376   5
0.54298465    6
0.386102588   7
0.147564719   8
NA            Two
0.083204676   1
0.030533656   2
0.905891284   3
NA            One
0.30843373    1
0.417785805   2
0.063145741   3
0.328035986   4

How can I do this? This would be a simple seq() solution if the length between non-NA values was constant, but this is not the case. It varies randomly between any two non-NA values.

Answer 1

Use sequence to generate a series of sequences defined by the distances between each text label in dat$Condition :

dat$new <- sequence(diff(c(which(!is.na(dat$Condition)),length(dat$Condition)+1)))-1
dat

#            X Condition new
#1          NA       One   0
#2  0.16935818      <NA>   1
#3  0.94108908      <NA>   2
#4  0.77227071      <NA>   3
#5  0.80954286      <NA>   4
#6  0.42623038      <NA>   5
#7  0.54298465      <NA>   6
#8  0.38610259      <NA>   7
#9  0.14756472      <NA>   8
#10         NA       Two   0
#11 0.08320468      <NA>   1
#12 0.03053366      <NA>   2
#13 0.90589128      <NA>   3
#14         NA       One   0
#15 0.30843373      <NA>   1
#16 0.41778581      <NA>   2
#17 0.06314574      <NA>   3
#18 0.32803599      <NA>   4
#19         NA       Two   0
#20 0.04524248      <NA>   1
#21 0.64039683      <NA>   2
#22 0.30109067      <NA>   3
#23 0.12732571      <NA>   4