CODEWITHSUNDEEP
raggregate
Ryan Simmons
Ryan Simmons

Reputation: 883

R data.frame ; get range of values in column

I cannot figure out how to do this. I have a data.frame in R. It looks like this:

Scores <- read.table(text = "
        ID Test1 Test2 Test3 Final
1 Student1    20    23    21    48
2 Student2    16    15    18    36
3 Student3    25    20    22    40
4 Student4    14    19    18    42
5 Student5    10    15    14    30
")

What I want is to create a new data object that has the range of values for each test, including the final. So it will look something like this:

result <- read.table(text = "
       min max
Test1  10  25
Test2  15  23
Test3  14  22
Final  30  48
")

It honestly doesn't matter to me whether it just lists the max and min values, or actually calculate the difference. I just can't figure out a way to implement this that isn't unnecessarily complicated. I know I can pull the columns out manually and individually, but there must be some better way of doing this. Something involving by() or tapply()? But I just cannot get them to work.

Any ideas?

Upvotes: 2

Views: 27127

Answers (6)

Aads
Aads

Reputation: 1

colrange<-function(x){
    sapply(x,range)
}

Make a colrange fucntion and insert your data: colrange(scores)

Upvotes: 0

deepak chaurasia
deepak chaurasia

Reputation: 1

(r_dd <- range(rdu_flights[5])), here rdu_flights is my data frame, [5] is the index number (you can find by using names("rdu_flights"), r_dd is the variable I am calling the range. I think this is pretty simple. I got the result as [1] -17 293 # represents the min and max values for departure delay of certain flights

Upvotes: 0

Metrics
Metrics

Reputation: 15458

Another approach: 

kk<-Map(function(x) cbind(x,min=min(Scores[,x]),max=max(Scores[,x])), as.list(names(Scores)[-1]))
data.frame(do.call(rbind,kk))
      x min max
1 Test1  10  25
2 Test2  15  23
3 Test3  14  22
4 Final  30  48

Upvotes: 0

dayne
dayne

Reputation: 7794

set.seed(1)
scores <- data.frame(ID=paste0("Student",1:5),
                     T1=sample(100,5),
                     T2=sample(100,5),
                     T3=sample(100,5),
                     Final=sample(100,5))

summ <- data.frame(min=apply(scores[,!grepl("ID",colnames(scores))],2,min),
                   max=apply(scores[,!grepl("ID",colnames(scores))],2,max))

> summ
      min max
T1     20  89
T2      6  94
T3     18  74
Final  37  98

Upvotes: 0

Se&#241;or O
Se&#241;or O

Reputation: 17432

A bit simpler:

> t(sapply(test, range))
  [,1] [,2]
a    1    3
b    2    5
d    1    2

Upvotes: 10

Matt Bannert
Matt Bannert

Reputation: 28274

Try this, reproducible example included.

test <- data.frame(a=c(1,2,3),b=c(2,3,5),d=c(1,2,2))
data.frame(min=sapply(test,min),max=sapply(test,max))

EDIT: Adding to @Blue Magister request for reproducible example: Look into ?dput ?structure to figure out how to post your data.frame here, e.g: dput(scores).

Upvotes: 1

Related Questions