Comment remodeler un data frame ?

Bonjour,

Code:

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df <- data.frame("Name" = c("a", "a", "b", "b", "b"),
                 "Sname" = c("az", "aze", "ba", "bo", "bi"),
                 "Number" = c(1, 2, 1, 4, 5),
                 "X" = c(100, 100, 100, 100, 100), stringsAsFactors = FALSE)
result <- data.frame("a" = c("az", "aze", NA),
                     "a-Number" = c(1, 2, NA),
                     "b" = c("ba", "bo", "bi"),
                     "b-Number" =c(1, 4, 5), stringsAsFactors = FALSE)

Code:

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> df
  Name Sname Number   X
1    a    az      1 100
2    a   aze      2 100
3    b    ba      1 100
4    b    bo      4 100
5    b    bi      5 100

Code:

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> result
     a a.Number  b b.Number
1   az        1 ba        1
2  aze        2 bo        4
3 <NA>       NA bi        5

• Avec la fonction reshape() :

Code:

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df$RepNo <- sequence(rle(as.vector(df$Name))$lengths)
result2 <- reshape(data=df[,-4],
                   idvar="RepNo",
                   v.names=c("Sname","Number"),
                   timevar="Name",
                   direction="wide")

Code:

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> result2
  RepNo Sname.a Number.a Sname.b Number.b
1     1      az        1      ba        1
2     2     aze        2      bo        4
5     3    <NA>       NA      bi        5

• ou "à la main" (notez la fonction setNames() qui permet de renommer les variables lors de la création du dataframe) :

Code:

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> dfa <- setNames(df[which(df$Name == "a"),c("Sname","Number")],c("a","a-Number"))
> dfa$No <- sequence(nrow(dfa))
> dfa
    a a-Number No
1  az        1  1
2 aze        2  2

Code:

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> dfb <- setNames(df[which(df$Name == "b"),c("Sname","Number")],c("b","b-Number"))
> dfb$No <- sequence(nrow(dfb))
> dfb
   b b-Number No
3 ba        1  1
4 bo        4  2
5 bi        5  3

Code:

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> result3 <- merge(dfa,dfb,by="No",all=TRUE)
> result3
  No    a a-Number  b b-Number
1  1   az        1 ba        1
2  2  aze        2 bo        4
3  3 <NA>       NA bi        5

Cordialement,