R data.frame ; get range of values in column

Question

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?

Looks like this is your first [r] question on StackOverflow. Welcome! Please see here about [making a reproducible example](http://stackoverflow.com/a/5963610) as a guide to help us answer your questions in this and future posts. — Blue Magister, Sep 19 '13 at 21:17

score 10 · Answer 1 · answered Sep 19 '13 at 21:26

10

A bit simpler:

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

answered Sep 19 '13 at 21:26

Señor O

17,049
2
45
47

3

Need to find a range, use `range()` - seems the most sensible option to me. – thelatemail Sep 19 '13 at 22:37
Is there a way to do this without getting duplicate values in the range? – Collective Action Jan 20 '18 at 05:54
@MichaelPerdue you mean like if the min and max of a range are the same number? – Señor O Jan 20 '18 at 17:29
@SenorO: if you only want unique values in your output. – Collective Action Jan 20 '18 at 19:42
1

@MichaelPerdue That's a different question. Search the site for how to remove duplicate rows in a data frame. – Señor O Jan 21 '18 at 17:34

score 1 · Accepted Answer · answered Sep 19 '13 at 21:17

1

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).

answered Sep 19 '13 at 21:17

Matt Bannert

27,631
38
141
207

Okay, thanks for helping! Fiddling around it seems like all I have to do then is use indexing (i.e. test[,i]) to get specific columns or ranges of them. Thanks a lot! – Ryan Simmons Sep 19 '13 at 21:25

score 0 · Answer 3 · answered Sep 19 '13 at 21:26

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

score 0 · Answer 4 · answered Sep 19 '13 at 21:34

0

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

answered Sep 19 '13 at 21:34

Metrics

15,172
7
54
83

score 0 · Answer 5 · answered Apr 17 '20 at 08:37

(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

score 0 · Answer 6 · edited Jul 08 '20 at 05:20

0

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

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

edited Jul 08 '20 at 05:20

aminography

21,986
13
70
74

answered Jul 08 '20 at 04:57

Aads

1

R data.frame ; get range of values in column

6 Answers6