== operand

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Hello,

You assigned 53 to c, not cc. Also, take a look at this:

http://cran.r-project.org/doc/FAQ/R-FAQ.html#Why-doesn_0027t-R-think-these-numbers-are-equal_003f
Hi,

I am trying to compare two values using "==" operand, please take a look of the following example (I copied ALL what I did here without deleting any line)

   bb<-1
cc<-50
cc==abs(bb+52)
[1] FALSE
C<-53
C<-53
c<-53
cc==abs(bb+52)
[1] FALSE

I am expecting to see a TRUE here. Then I tried another way,

abs(1+52)
[1] 53
cc==abs(1+52)
[1] FALSE

Why it is FALSE. Then I tried

d<-abs(b+52)
Error: object "b" not found
d<-abs(bb+52)
d
[1] 53
c==d
[1] TRUE

Now it is TRUE, but a wired thing is as following,
c==abs(bb+52)
[1] TRUE

The coding "c==abs(bb+52)" is just the same from the 3line in the top, why 2 different results? HOWEVER, it is not repeatable, I am glad I did not close the window.

Also,
c<-0.5-0.1
n<-0.6-0.2
n==c
[1] FALSE

So, is "==" comparing formula or result?

Thanks,
Renny

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Hi,

I am trying to compare two values using "==" operand, please take a look of the following example (I copied ALL what I did here without deleting any line)

   bb<-1
cc<-50
cc==abs(bb+52)
[1] FALSE
C<-53
C<-53
c<-53
cc==abs(bb+52)
[1] FALSE
cc is 50.  bb is 1.  Why do you expect 50 to equal 1 + 52?  Perhaps
you meant to type cc <- 53 ?

Hadley
http://had.co.nz/
Hi,
?
I am trying to compare two values using "==" operand, please take a look
of the following example (I copied ALL what I did here without deleting
any line)
?
??? bb<-1
cc<-50
cc==abs(bb+52)
[1] FALSE
C<-53
C<-53
c<-53
cc==abs(bb+52)
[1] FALSE??????????? 
?
I am expecting to see a TRUE here. 

Why?  You are modifying the variables C and c, but not cc.
Perhaps you are confused about the == operator, which
doesn't do assignments -- it only tests equality.
Then I tried another way,
?
abs(1+52)
[1] 53
cc==abs(1+52)
[1] FALSE

Why it is FALSE.

Because cc is 50, which isn't equal to 53?
 Then I tried

d<-abs(b+52)
Error: object "b" not found
d<-abs(bb+52)
d
[1] 53
c==d
[1] TRUE

Now it is TRUE, 

Which makes sense because c is 53 and d is 1+52 (i.e., 53)
but a wired thing is as following,
c==abs(bb+52)
[1] TRUE

The coding "c==abs(bb+52)" is just the same from the 3line in the top, why
2 different results? HOWEVER, it is not repeatable, I am glad I did not
close the window.

It's different, because cc and c are different
Also, 
c<-0.5-0.1
n<-0.6-0.2
n==c
[1] FALSE

For this one, you need to see FAQ 7.31 ...
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