[R] Histogram from a single column of a data frame

Rolf Turner r.turner at auckland.ac.nz
Sat Sep 27 00:32:03 CEST 2014

On 27/09/14 05:57, Richard Lerner wrote:
> Column 7 of "oded" is "Breed". If I enter
>> summary(Breed)
> I get the counts of the numbers in each breed.
> However, if I enter
> I have tried
>> hist($Breed)
> Error: unexpected '$' in "hist($"
>> hist(Breed)
> Error in hist(Breed) : object 'Breed' not found
>> hist("Breed")
> Error in hist.default("Breed") : 'x' must be numeric
>> colnames(oded)
> [1] "Subject.Name"       "Date"               "Species"
> "Age"                "Sex"
> [6] "Spayed....Neutered" "Breed"              "Breed.Code"
> How do I get a histogram of the counts in column 7?

Are you for real, or is this some kind of joke?

Assuming it's not a joke:

(1) Look at ?"$".

(2) WTF do you expect hist($Breed) to do?  Where is "Breed" going to be 
found, for pity's sake?  You appear to have no understanding of how R 
(or any programming language) works.

Read the Introduction to R manual and *get* some understanding if you 
are going to use R.

(3) The correct usage obviously (and I mean ***really***; it *IS* 
obvious) is hist(oded$Breed) --- which tells hist() where to find "Breed".

(4) You could also use


which is a useful syntax in some circumstances.


Rolf Turner

Rolf Turner
Technical Editor ANZJS

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