CODEWITHSUNDEEP
rdataframe
user44552
user44552

Reputation: 161

Reordering data columns

I tried to reorder my columns but unable to figure out how to do it for a certain order in my column. For eg. I have the following data.frame

df <- data.frame(name=c("a","a","a","b","b","c","c","c","c"), time=c("screen","third","second","first","second","fourth","third","first","screen"), first_values=c("0.11", "0.23", "0.03", "0.4", "0.10", "0.25", "0.87","0.11","0.21"), second_values=c("0.05", "0.32", "0.63", "0.67", "0.10", "0.25", "0.87","0.11","0.91"))

target.time <- c("zeros", "screen", "first", "second", "third", "fourth")

So my goal is to order by name and by time; but time needs to be in the order described by target.time.

I can achieve multiple column ordering by doing the following;

df_reorder <- df[order(df$name, df$time), ]

But I don't know how to order time with target.time order while df$name remains unique for the pertinent rows.

Upvotes: 1

Views: 69

Answers (1)

lmo
lmo

Reputation: 38520

One common method is to reorder the factor levels of df$time and then use order.

# reassign factor levels according to target.time
df$time <- factor(df$time, levels=target.time)

# order data.frame
df[order(df$name, df$time),]
  name   time first_values second_values
1    a screen         0.11          0.05
3    a second         0.03          0.63
2    a  third         0.23          0.32
4    b  first          0.4          0.67
5    b second         0.10          0.10
9    c screen         0.21          0.91
8    c  first         0.11          0.11
7    c  third         0.87          0.87
6    c fourth         0.25          0.25

Upvotes: 4

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