{"id":122545,"date":"2015-02-18T19:03:29","date_gmt":"2015-02-18T13:33:29","guid":{"rendered":"http:\/\/analyticstraining.com\/?p=5996"},"modified":"2020-06-01T16:37:44","modified_gmt":"2020-06-01T11:07:44","slug":"using-pipes-r","status":"publish","type":"post","link":"https:\/\/www.jigsawacademy.com\/using-pipes-r\/","title":{"rendered":"Using Pipes in R"},"content":{"rendered":"

By: Gunnvant Singh<\/strong>, Faculty at Jigsaw<\/p>\n

 <\/p>\n

Let’s be honest, once you start doing serious data wrangling in R, the code starts appearing ugly. One of the reason for this is the functional nature of R. In order to accomplish a decent data manipulation task one has to write nested functions. Now, writing nested functions is not that difficult, what’s difficult is reading them!!! Sample the code below:<\/span><\/span><\/p>\n

<\/p>\n

library(babynames)<\/span><\/span><\/p>\n

libary(dplyr)<\/span><\/span><\/p>\n

data(babynames)<\/span><\/span><\/p>\n

head(babynames)<\/span><\/span><\/p>\n

sum(select(filter(babynames,sex==”F”,name==”Mary”),n))<\/span><\/span><\/p>\n

Now, if you pay attention to the last line it takes a while to figure out what is happening in that piece of code. Let me break it down for you:<\/span><\/span><\/p>\n

1. First I subset the data based on sex and name. Essentially the line of code filter(babynames,sex==”F”,name==”Mary”) is selecting all the observations in the data where the gender is female and name is Mary.<\/span><\/span><\/p>\n

2. After this, the command ‘select’ is being used to pick the column named ‘n’ from the subsetted data.<\/span><\/span><\/p>\n

3. The function sum() is being used to add the numbers present in the selected column ‘n’.<\/span><\/span><\/p>\n

Now, the key to understand this line of code is to read it from inside out. Now, you all will agree that this is not a very straightforward and one has to think through to understand the piece of code.<\/span><\/span><\/p>\n

What we just did above by nesting functions ‘filter’, ‘select’ and ‘sum’ is called function composition.<\/i> Essentially if I have functions ‘f’, ‘g’ and ‘z’ , this is what I am trying to achieve through nesting:<\/span><\/span><\/p>\n

z(g(f(x)))) ~ sum(select(filter(data))).<\/span><\/span><\/p>\n

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