R: Adding NAs into Data Frame

Question

I have a data frame like so:

Name   Position   Value
a         1        0.2
a         3        0.4
a         4        0.3
b         1        0.5
b         2          


        

Answer 1

You can use the reshape2 package:

# make sample data frame
df <- read.table(text = "Name   Position   Value
a         1        0.2
a         3        0.4
a         4        0.3
b         1        0.5
b         2        0.4
b         5        0.3
c         2        0.3
c         3        0.4
c         5        0.1
d         1        0.2
d         2        0.4
d         3        0.5", header = TRUE, stringsAsFactors = FALSE)

library('reshape2')
df2 <- dcast(df, Name ~ Position)
df3 <- melt(df2, value.name = "Value", variable.name = "Position")
df3[order(df3$Name), ]
#    Name Position Value
# 1     a        1   0.2
# 5     a        2    NA
# 9     a        3   0.4
# 13    a        4   0.3
# 17    a        5    NA
# 2     b        1   0.5
# 6     b        2   0.4
# 10    b        3    NA
# 14    b        4    NA
# 18    b        5   0.3
# 3     c        1    NA
# 7     c        2   0.3
# 11    c        3   0.4
# 15    c        4    NA
# 19    c        5   0.1
# 4     d        1   0.2
# 8     d        2   0.4
# 12    d        3   0.5
# 16    d        4    NA
# 20    d        5    NA