CODEWITHSUNDEEP
r
gd1035
gd1035

Reputation: 103

Trying to understand the output of this pipe operation in r

I am learning r and currently am looking at the pipe operator %>%, found in the magrittr package. When I try the following: 

pi/2 %>% sin

The result is 3.454967, which is incorrect

Instead when I do:

(pi/2) %>% sin

The result is 1, which is correct.
I am curious what is happening in the first case, from looking through the documentation here. I am unable to find anything useful. Could someone point me in the direction of some documentation for understanding this?

Upvotes: 0

Views: 37

Answers (1)

MrFlick
MrFlick

Reputation: 206596

The order in which functions are evaualted depend on the operator precedence rules descrubed in the ?Syntax help page

:: :::   access variables in a namespace
$ @      component / slot extraction
[ [[     indexing
^        exponentiation (right to left)
- +      unary minus and plus
:        sequence operator
%any%    special operators (including %% and %/%)
* /      multiply, divide
+ -      (binary) add, subtract
< > <= >= == !=  ordering and comparison
!        negation
& &&     and
| ||     or
~        as in formulae
-> ->>   rightwards assignment
<- <<-   assignment (right to left)
=        assignment (right to left)
?        help (unary and binary)

Note that %% functions have higher precedence then / so they are run first. So essentially you are running

pi/(2 %>% sin)
# pi/0.9092974
# [1] 3.454967

Upvotes: 3

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