Tutorials on Amit Kohli

How to create an R package, easy mode

Tue, 07 Jan 2020 00:00:00 +0000

Creating an R package can be a daunting task, but there are several tools to facilitate this process immensely. Of course, each approach has a series of advantages and drawbacks, so it is very much a subjective thing. Since I have changed my mind and worked on this task frequently, here’s a conclusive* guide of the steps I follow. (* This guide will never be finished, so watch this space, I’ll be coming back to make edits as they seem appropriate).

Setting up twitter streamR Service on an Ubuntu server

Tue, 07 Nov 2017 15:56:06 +0000

I am working on a super-secret project for which I am harvesting a highly confidential source of data: twitter 🙂 The idea is to gather a small amount of twitter data, but for a long time… maybe a year. I tried to use the package TwitteR, but it can only grab up to a week of tweets… it’s not really good for a set-it-and-forget-it ongoing capture since it requires user-based authentication, which means (I guess) that a machine can’t authenticate for it. Tangibly this means a human needs to start the process every time. So I could run the script weekly, but of course there’s days you miss, or run at different times… plus it’s just plain annoying…

Track your local R scheduled tasks with CommandCenter2000!!!

Sun, 29 May 2016 17:32:02 +0000

There are many ways to automate your scripts running, for example using RScript, or in-R itself (and now even as an add-in for RStudio) (check all here). But after a while, it can get a bit overwhelming to track tasks and ensure they are firing as planned. In order to address this, I have developed some futuristic advanced tech that lets us do that. I hereby present to you: the CommandCenter2000!!! Yes, it’s Y2K compliant! This is what it looks like:

Make dashboard Tiles/Notecards in R

Thu, 25 Feb 2016 19:47:39 +0000

Update!!
#

Due to the popularity of this script, I released it as a package. To install it, use:

KPI dashboard in R with animated icons

Fri, 12 Feb 2016 10:08:04 +0000

So Key Performance Indicators (KPIs) are all the rage in the dashboarding community… well So Key Performance Indicators (KPIs) are all the rage in the dashboarding community… well really. The premise is simple… check a list of measurements against targets and show how they compare using some kind of [[Visualization]]. I haven’t yet seen, however, a version that can utilize animated icons to display indicators that REALLY need attention. So here you go, a tutorial on how to make your very own animated icon KPI, using the googleVis library.

How to move ODBC DSN information from one computer to another

Thu, 29 Oct 2015 19:02:49 +0000

YAAAAAAAAY!!!! I got a new computer!!

Oh crap how do I move the DSN connections that I made on this computer?? This is how (assuming you’re on windows)! But before, we do, we have to make sure we have the right drivers… so lemme first go over the basikses my precious:

Excel is how I do maps…

Wed, 08 Jul 2015 15:15:55 +0000

Following the footsteps of this cool post I saw by JohnNelsonIDV, I wanted to try to and make a map using Excel.

Fast forward 2 days and the opportunity came up. Lo and behold, a Map of Reference Evapotranspiration built in Excel!

Best way to make a custom palette with ggplot2

Fri, 27 Feb 2015 18:38:44 +0000

A better way to pick colours with ggplot2

First, get the excellent package by Marco D Visser:

Best way to unclog drains

Thu, 19 Feb 2015 18:00:47 +0000

Check out my new instructable on how to clear clogs without using chemicals.

Check it out on instructables.com!

Excel basics

Mon, 16 Feb 2015 18:32:22 +0000

Most of the things posted on this page will make reference to Visual Basic for Applications (VBA).

How do you get to the Visual Basic Editor?
#

Excel versions prior to 2007:
#

Under the Tools menu, go to Macros, and the option should be there.

Excel 2007:
#

Available through the Developer tab on the ribbon. If you don’t see a developer tab:

Human armature from d3Network!

Tue, 11 Nov 2014 00:17:06 +0000

So a little bit of R, a little bit of d3Network and boom! Instant interactive html human!

<style>
.link {
stroke: #666;
opacity: 0.4;
stroke-width: 1.5px;
}
.node circle {
stroke: #fff;
opacity: 0.4;
stroke-width: 1.5px;
}
.node:not(:hover) .nodetext {
display: none;
}
text {
font: 7px serif;
opacity: 0.4;
pointer-events: none;
}
</style>

<script src=http://d3js.org/d3.v3.min.js></script>

<script> 
 var links = [ { "source" : 0, "target" : 1, "value" : 300 }, { "source" : 1, "target" : 2, "value" : 50 }, { "source" : 1, "target" : 3, "value" : 50 }, { "source" : 2, "target" : 4, "value" : 20 }, { "source" : 3, "target" : 5, "value" : 20 }, { "source" : 4, "target" : 6, "value" : 1 }, { "source" : 5, "target" : 7, "value" : 1 }, { "source" : 8, "target" : 9, "value" : 50 }, { "source" : 9, "target" : 10, "value" : 20 }, { "source" : 9, "target" : 11, "value" : 20 }, { "source" : 10, "target" : 12, "value" : 10 }, { "source" : 11, "target" : 13, "value" : 10 }, { "source" : 12, "target" : 14, "value" : 5 }, { "source" : 13, "target" : 15, "value" : 5 }, { "source" : 2, "target" : 8, "value" : 50 }, { "source" : 3, "target" : 16, "value" : 50 }, { "source" : 1, "target" : 8, "value" : 50 }, { "source" : 1, "target" : 16, "value" : 50 }, { "source" : 8, "target" : 16, "value" : 50 }, { "source" : 16, "target" : 9, "value" : 50 } ] ; 
 var nodes = [ { "name" : "Head", "group" : 1 }, { "name" : "Sternum", "group" : 1 }, { "name" : "Shoulder.r", "group" : 1 }, { "name" : "Shoulder.l", "group" : 1 }, { "name" : "Elbow.r", "group" : 1 }, { "name" : "Elbow.l", "group" : 1 }, { "name" : "Wrist.r", "group" : 1 }, { "name" : "Wrist.l", "group" : 1 }, { "name" : "rib.r", "group" : 1 }, { "name" : "hip.c", "group" : 1 }, { "name" : "hip.r", "group" : 1 }, { "name" : "hip.l", "group" : 1 }, { "name" : "knee.r", "group" : 1 }, { "name" : "knee.l", "group" : 1 }, { "name" : "ankle.r", "group" : 1 }, { "name" : "ankle.l", "group" : 1 }, { "name" : "rib.l", "group" : 1 } ] ; 
 var width = 900
height = 600;

var color = d3.scale.category20();

var force = d3.layout.force()
.nodes(d3.values(nodes))
.links(links)
.size([width, height])
.linkDistance(50)
.charge(-120)
.on("tick", tick)
.start();

var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);

var link = svg.selectAll(".link")
.data(force.links())
.enter().append("line")
.attr("class", "link")
.style("stroke-width", function(d) { return Math.sqrt(d.value); });

var node = svg.selectAll(".node")
.data(force.nodes())
.enter().append("g")
.attr("class", "node")
.style("fill", function(d) { return color(d.group); })
.style("opacity", 0.4)
.on("mouseover", mouseover)
.on("mouseout", mouseout)
.call(force.drag);

node.append("circle")
.attr("r", 6)

node.append("svg:text")
.attr("class", "nodetext")
.attr("dx", 12)
.attr("dy", ".35em")
.text(function(d) { return d.name });

function tick() {
link
.attr("x1", function(d) { return d.source.x; })
.attr("y1", function(d) { return d.source.y; })
.attr("x2", function(d) { return d.target.x; })
.attr("y2", function(d) { return d.target.y; });

node.attr("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"; });
}

function mouseover() {
d3.select(this).select("circle").transition()
.duration(750)
.attr("r", 16);
d3.select(this).select("text").transition()
.duration(750)
.attr("x", 13)
.style("stroke-width", ".5px")
.style("font", "17.5px serif")
.style("opacity", 1);
}

function mouseout() {
d3.select(this).select("circle").transition()
.duration(750)
.attr("r", 8);
}

</script>

Epic lamp instructable posted

Tue, 04 Nov 2014 21:17:31 +0000

What do you do with a box of 100 slides that you’ve had for 10 years?

BOOM. This is what. Check out the instructable showing the steps!

kml maker for Excel -> Google Earth

Wed, 02 Jul 2014 12:36:43 +0000

I made a userform that quickly and easily allows you to make a kml file that’s readable by google earth based on some excel dataset that has coordinates.

Features:

Simple and advanced modes
userform for convenience
Icons change when highlighted
Allows html to be passed to popup contents, everything is customizable
Issue a default icon, and change icons for specific points
Change colours and opacity for points via easy dropdowns
Pass data from excel columns to the popup for each point

I’ve taken the liberty to make an excel file with the form, and some examples and showcasing the features so you know how to do it. Check it out and please provide comments!

Change lists into tables and tables into lists

Fri, 29 Mar 2013 15:04:29 +0000

Designed a userform that converts dimension formats, i.e. information from tabular format to list (or flat) format, and viceversa. Some options include preserving formatting or not, as well as including blank cells or not.

Search or filter through controls in a userform

Sat, 09 Feb 2013 18:30:30 +0000

This bit might be useful if you have a lot of controls on a form, and need a quick way to highlight them. This post supports the video:

I uploaded a video tutorial, you can see it here (please view in fullscreen mode, or watch the video in youtube by clicking on the youtube logo):[http://www.youtube.com/watch?v=5RtV9msZ2RE].

Compare lists and identify matches macro

Thu, 07 Feb 2013 16:24:52 +0000

This macro provides an alternative to vlookup (which looks at two lists and provides data from one list to the second) that retains similar functionality while providing certain benefits. It accomplishes this by physically moving one list to the other. It’s impossible to get a false positive, and it doesn’t provide that annoying /#N/A that messes up calculations.

Macro userform – a good visual way to organise macros

Thu, 07 Feb 2013 16:22:10 +0000

At a certain point it can become challenging to quickly find and run the macro we need. Below are some options to organize our macros. I will focus on using a pop-up form because it’s the method I prefer, but at the bottom of the article, you can see other options.