[R] How to locate the difference from two data frames

Erik Iverson eriki at ccbr.umn.edu
Thu Apr 8 03:55:40 CEST 2010

Jun Shen wrote:
> Hi, David,
> Thanks for the reply. However str() doesn't tell me exactly which element is
> different. I expect to see a is identical to b. But if there is some minor
> difference (usually by human mistake), I want to know which element
> (numerical or character) is different.

So you're saying you have two data.frames with the same dimensions and want to 
know which elements are different?  What about different attributes such as 
names, labels, etc?

A very naive first attempt might be something like:

df1 <- data.frame(a = 1:10, b = 2:11)
df2 <- data.frame(a = 1:10, b = c(2:10, 12))

mapply("==", df1, df2)

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