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Month: June 2018

Using FlashText Instead Of RegEx

Published 2018-06-21 by Kevin Feasel

Leona Zhang compares the FlashText Python library to using regular expressions:

If you have done any text/data analysis, you might already be familiar with Regular Expressions (RegEx). RegEx evolved as a necessary tool for text editing. If you are still using RegEx to deal with text processing, then you may have some problems to deal with. Why? When it comes to large-sized texts, the low efficiency of RegEx can make data analysis unacceptably slow.

In this article, we will discuss how you can use FlashText, a Python library that is 100 times faster than RegEx to perform data analysis.

Learn more on the GitHub repo.  I haven’t used this before but I could see it being handy.

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Neural Networks Are Polynomial Regression

Published 2018-06-21 by Kevin Feasel

Norman Matloff announces a new paper:

A summary of the paper is:

  • We present a very simple, informal mathematical argument that neural networks (NNs) are in essence polynomial regression (PR). We refer to this as NNAEPR.

  • NNAEPR implies that we can use our knowledge of the “old-fashioned” method of PR to gain insight into how NNs — widely viewed somewhat warily as a “black box” — work inside.

  • One such insight is that the outputs of an NN layer will be prone to multicollinearity, with the problem becoming worse with each successive layer. This in turn may explain why convergence issues often develop in NNs. It also suggests that NN users tend to use overly large networks.

  • NNAEPR suggests that one may abandon using NNs altogether, and simply use PR instead.

  • We investigated this on a wide variety of datasets, and found that in every case PR did as well as, and often better than, NNs.

  • We have developed a feature-rich R package, polyreg, to facilitate using PR in multivariate settings.

The paper and presentation slides are ungated, so check it out.  H/T R-bloggers

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Strings And Identifiers

Published 2018-06-21 by Kevin Feasel

Kenneth Fisher explains the difference between a string and an identifier:

A common mistake, and one I make frequently myself is to use a string in place of an identifier, or vise-versa. So to start, let’s have some definitions, shall we?

String

a linear sequence of characters, words, or other data.

Identifier

a sequence of characters used to identify or refer to a program or an element, such as a variable or a set of data, within it.

And because I always find examples fairly useful.

Click through for the example as well as additional explanation.

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Power BI Helper Version 2.0 Released

Published 2018-06-21 by Kevin Feasel

Reza Rad has a new version of Power BI Helper:

I started Power BI Helper with the intention to help to find issues in Power BI reports faster and easier. This tool over time became better and better. I’m excited now to let you know that the version 2.0 of this product is now available for everyone to use and enjoy. This version comes with these features:

  • Connecting to more than one Power BI model. Selection option for the model.

  • Showing the connection mode of the Power BI file.

  • Showing list of tables that are NOT used in any visualization, and can be hidden from the report.

  • Modeling advises

    • List of both directional relationships
    • List of inactive relationships

  • Some minor bug fixes

It looks like quite the useful tool.

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Replicating Extra-Long Strings

Published 2018-06-21 by Kevin Feasel

Monica Rathbun walks us through a replication error:

Ever seen the below error? Until this week I hadn’t. So, I figured I’d take a little time and introduce it to those that had not.

Error Description: Length of LOB data (65754) to be replicated exceeds configured maximum 65536. Use the stored procedure sp_configure to increase the configured maximum value for max text repl size option, which defaults to 65536. A configured value of -1 indicates no limit

We ran into an issue with a customer this week, this error was flooding the error log. After a little digging I found it had to do with transactional replication (also applies to Change Data Capture) they had setup which included LOB data.

Read on to see what you can do to resolve this error.  Also, check out the comments and be glad you’re not in that boat…unless you are, in which case…

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DATENAME In SQL Server

Published 2018-06-21 by Kevin Feasel

Randolph West continues his dates and times series with a new function, DATENAME():

There are many similarities between DATEPART and DATENAME. Where DATEPART returns the date or time part as an integer, DATENAME returns the part as a character string.

This DATENAME function also takes two parameters: the date or time part we want back, and the input date. Just as we saw with DATEPART, the documentation indicates the input date parameter must be an “expression that can resolve to one of the following data types: date, smalldatetime, datetime, datetime2, datetimeoffset, or time.”

Similarly, the date and time parts that can be returned look much like those in DATEPART, which gives us another opportunity for the reminder that we should avoid using the available abbreviations in order to help with writing clearly understandable code.

DATENAME is a useful function for displaying parts of dates & times, but Randolph does lay out the caveats.

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Azure Without ARM

Published 2018-06-21 by Kevin Feasel

Ed Elliott gives us a few ways of deploying Azure resources without using ARM templates:

So, what are our options?

  • Create/Edit/Delete ourselves using Powershell/.Net/Python/Go/Java/Some Other SDK

  • Process something else (YAML?) into JSON

  • Generate the ARM using c#/Powershell/something else

  • 3rd party tools, (Terraform is the big daddy) / others include Sparkle Formation

To be honest, I’d probably just stick with ARM templates.

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SQL Operations Studio, June Release

Published 2018-06-21 by Kevin Feasel

Alan Yu announces the June release of SQL Operations Studio:

The June public preview release is focused on improving our Extensibility experience with the release of new extensions as well as addressing top GitHub issues.

Highlights for this build include the following.

  • SQL Server Profiler for SQL Operations Studio Preview extension initial release

  • Azure SQL Data Warehouse extension

  • Edit Data Filtering and Sorting

  • SQL Server Agent for SQL Operations Studio Preview extension enhancements for Jobs and Job History views

  • Build your own SQL Ops Studio extension

  • Visual Studio Code Refresh

  • Fix GitHub Issues

I saw “SQL Server Profiler” and started wondering what was going on, until Alan explained that it’s actually the lightweight Extended Events profiler and not the heavyweight beast we know and love and/or hate.

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Using DALEX To Explain Black-Box Models

Published 2018-06-20 by Kevin Feasel

Przemyslaw Biecek explains that there’s more than LIME for explaining black-box models:

I’ve heard about a number of consulting companies, that decided to use simple linear model instead of a black box model with higher performance, because ,,client wants to understand factors that drive the prediction’’.
And usually the discussion goes as following: ,,We have tried LIME for our black-box model, it is great, but it is not working in our case’’, ,,Have you tried other explainers?’’, ,,What other explainers’’?

So here you have a map of different visual explanations for black-box models.

Check out DALEX, which includes a Jupyter notebook example.  H/T R-Bloggers

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Comparing Keras In Python Versus R

Published 2018-06-20 by Kevin Feasel

Dmitry Kisler performs image classification using Keras in both Python and R:

From the plots above, one can see that:

  • the accuracy of your model doesn’t depend on the language you use to build and train it (the plot shows only train accuracy, but the model doesn’t have high variance and the bias accuracy is around 99% as well).

  • even though 10 measurements may be not convincing, but Python would reduce (by up to 15%) the time required to train your CNN model. This is somewhat expected because R uses Python under the hood when executes Keras functions.

This is just one example, but the results are about what I’d expect.

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