[R] Boolean expression

[Jim Lemon]

Hi Jue,
The character sequence "<-" is preferentially interpreted as "assign the
value on the right to the name on the left". You can use parentheses to
force the unary minus to be interpreted:

if(a<(-1))

or you can just break the sequence with a space:

if(a< -1)

One less character, but perhaps easier to misread.

Jim


On Mon, Sep 14, 2015 at 9:10 PM, Jue Lin-Ye <jl.iccp at gmail.com> wrote:

> Dear fellow R users,
>
> I would like to discuss something. First of all, I would like to make clear
> that I think that the current R software is great.
>
> I have noticed that, for example, in the boolean expression "if(a<-1)", it
> is not clear if what is asked is "if 'a' is 1" or "if 'a' is lesser than
> -1". Should we just enclose "-1" within parentheses or should we have a
> more unequivocal syntax, here, like "a<$", "a<%"?
>
> Best regards,
>
> ​Jue
>
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>
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