R Tip: Use match_order() to Align Data
R tip. Use wrapr::match_order() to align data. Suppose we have data in two data frames, and both of these data frames have common row-identifying columns called “idx“. library("wrapr") d1 [Read more...]
Articles by John Mount
magrittr and wrapr Pipes in R, an Examination
Let’s consider piping in R both using the magrittr package and using the wrapr package. magrittr pipelines The magittr pipe glyph “%__%” is the most popular piping symbol in R. magrittr documentation describes %__% as follow. Basic piping: x %__% f is equivalent to f(x) x %__% f(y) is equivalent to ... [Read more...]
Four Years of Practical Data Science with R
Four years ago today authors Nina Zumel and John Mount received our author’s copies of Practical Data Science with R! It has its imitators, but it remains the best “I have R, now what do I do with it?” book (as it works the user through non-trivial projects, analyses, ...
R Tip: Think in Terms of Values
R tip: first organize your tasks in terms of data, values, and desired transformation of values, not initially in terms of concrete functions or code. I know I write a lot about coding in R. But it is in the service of supporting statistics, analysis, predictive analytics, and data science. ... [Read more...]
Hangul/Korean edition of Practical Data Science with R!
Excited to see our new Hangul/Korean edition of “Practical Data Science with R” by Nina Zumel, John Mount, translated by Daekyoung Lim. Thank you for producing a handsome edition, Manning and JPub.kr!
R Tip: Use Named Vectors to Re-Map Values
Here is an R tip. Want to re-map a column of values? Use a named vector as the mapping. Example: library("dplyr") library("wrapr") head(starwars[, qc(name, gender)]) # # A tibble: 6 x 2 # name gender # # 1 Luke Skywalker male # 2 C-3PO NA # 3 R2-D2 NA # 4 Darth Vader … Continue reading R Tip: Use ... [Read more...]
R Tip: Use let() to Re-Map Names
Another R tip. Need to replace a name in some R code or make R code re-usable? Use wrapr::let(). Here is an example involving dplyr. Let’s look at some example data: library("dplyr") library("wrapr") starwars %__% select(., name, homeworld, species) %__% head(.) # # A tibble: 6 x 3 # name homeworld species # … Continue ...
R Tip: Break up Function Nesting for Legibility
There are a number of easy ways to avoid illegible code nesting problems in R. In this R tip we will expand upon the above statement with a simple example. At some point it becomes illegible and undesirable to compose operations by nesting them, such as in the following code. ...
R Tip: Use stringsAsFactors = FALSE
R tip: use stringsAsFactors = FALSE. R often uses a concept of factors to re-encode strings. This can be too early and too aggressive. Sometimes a string is just a string. Sigmund Freud, it is often claimed, said: “Sometimes a cigar is just a cigar.” To avoid problems delay re-encoding of ...
Take Care If Trying the RPostgres Package
Take care if trying the new RPostgres database connection package. By default it returns some non-standard types that code developed against other database drivers may not expect, and may not be ready to defend against. Danger, Will Robinson! Trying the new package One can try the newer RPostgres as a ... [Read more...]
The Many Faces of R
Some days I see R as an eclectic programming language preferred by scientists. “Programming languages as people.” From Leftover Salad (David Marino). Other days I see it more like the following. “Statistical tools as cars.” Shared previously by Darren L. Dhaly and brought to my attention by post by Dimitri ...
R Tip: Use the vtreat Package For Data Preparation
If you are working with predictive modeling or machine learning in R this is the R tip that is going to save you the most time and deliver the biggest improvement in your results. R Tip: Use the vtreat package for data preparation in predictive analytics and machine learning projects. ...
R Tip: Introduce Indices to Avoid for() Class Loss Issues
Here is an R tip. Use loop indices to avoid for()-loops damaging classes. Below is an R annoyance that occurs again and again: vectors lose class attributes when you iterate over them in a for()-loop. d [1] "2018-02-18 10:16:16 PST" "2018-02-18 10:16:16 PST" for(di in d) { print(di) } #__ … ... [Read more...]
R Tip: Use vector(mode = “list”) to Pre-Allocate Lists
Another R tip. Use vector(mode = "list") to pre-allocate lists. result [[1]] #__ NULL #__ #__ [[2]] #__ NULL #__ #__ [[3]] #__ NULL The above used to be critical for writing performant R code (R seems to have greatly improved incremental list growth over the years). It … Continue reading R Tip: Use vector(mode = "list") to Pre-Allocate Lists
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R Tip: Get Out of the Habit of Calling View() Directly
R tip: get out of the habit of calling View() directly. View() only works correctly in interactive environments, not currently in RMarkdown contexts. It is better to call something else that safely dispatches to View(), or to something else depending if you are in an interactive or non-interactive session. The ... [Read more...]
Speaking on New Tools for R at Big Data Scale
I would like to thank LinkedIn for letting me speak with some of their data scientists and analysts. John Mount discussing rquery SQL generation at LinkedIn. If you have a group using R at database or Spark scale, please reach out ( jmount at win-vector.com ). We (Win-Vector LLC) have some ...
R Tip: Make Arguments Explicit in magrittr/dplyr Pipelines
I think this is the R Tip that is going to be the most controversial yet. Its potential pitfalls include: it is a style prescription (which makes it different than and less immediately useful than something of the nature of R Tip: Force Named Arguments), and it is heterodox (this ... [Read more...]
R Tip: Use drop = FALSE with data.frames
Another R tip. Get in the habit of using drop = FALSE when indexing (using [ , ] on) data.frames. Prince Rupert’s drops (img: Wikimedia Commons) In R, single column data.frames are often converted to vectors when manipulated. For example: d x #__ 1 1 #__ 2 2 #__ … Continue reading R Tip: Use drop = FALSE with data....
Wanted: cdata Test Pilots
I need a few volunteers to please “test pilot” the development version of the R package cdata, please. Jacqueline Cochran: at the time of her death, no other pilot held more speed, distance, or altitude records in aviation history than Cochran. Our cdata package has an upcoming new feature called “...
Is R base::subset() really that bad?
Is R base::subset() really that bad? Notes discussing subset() often refer to the following text (from help(subset), referred to in examples: 1, 2): Warning This is a convenience function intended for use interactively. For programming it is better to use the standard sub-setting functions like [, and in particular the non-standard ...
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