Tag: column

Feed: R-bloggers. Author: John Johnson. So the goal here is to focus back on Greenville County and have even more granularity. I look at median house prices near Greenville and then overlay the park data downloaded earlier. This time, for the Census data, I use the tidycensus package that came out recently. Furthermore, instead of using ggplot2 to create a static map, I use the leaflet package to create an interactive map, and, furthermore integrate data from disparate sources in a convenient way.The local parks file can be found here courtesy of a small group of dedicated volunteers and an ... Read More

Feed: Featured Blog Posts - Data Science Central. Author: HAN Lijun.   By JIANG Buxing, Data Scientist  Multidimensional analysis, commonly called OLAP, is an interactively data analysis process that performs operations, including rotation, slice and dice, drilldown etc., on a data cube. The structure of its back-end computation is simple, as shown by the following SQL: SELECT D,..., SUM(M), ... FROM C WHERE D'=d' AND ... GROUP BY D,... The statement aggregates some measures by some dimensions. C is a data cube, D,… represents dimensions to be selected, and M,… represents measures to be aggregated. Except for SUM, we can ... Read More

Feed: Featured Blog Posts - Data Science Central. Author: Amelia Matteson. This article was written by Michael Rundell. A Curated List of Data Science Interview Questions Preparing for an interview is not easy – naturally there is a large amount of uncertainty regarding the data science interview questions you will be asked. No matter how much work experience or technical skill you have, an interviewer can throw you off with a set of questions that you didn’t expect. For a data science interview, an interviewer will ask questions spanning a wide range of topics, requiring strong technical knowledge and communication ... Read More

Feed: What's New. Today, we improved the way you work with both of these new features by enabling the IAM console to remember your preferences for table column selections and IAM policy viewing and editing.  Now when you select columns on the users list or policy list pages, the console will remember your selection and render these columns the next time you load that page. The IAM console also will remember if you last viewed a policy using the policy summary view or the JSON view. The next time you view any policy, the console will render the policy using ... Read More

Feed: IDERA Community Blog; Author: billellis; B-tree indices in Oracle are powerful.  Sometimes a very good index can be even better.  Precise for Oracle helps DBAs recognize this situation.This screen excerpt (please click on it to enlarge) from Precise for Oracle identifies that 20% of execution time is spent accessing the index TD_FN_X1 in a Heavy Index Range Scan.  This SQL statement sums AMOUNT for similar FIRST_NAMEs.                                                               Checking on ... Read More

Feed: R-bloggers. Author: Florian Privé. In this post, I will talk about my package bigstatsr, which I’ve just presented in a lightning talk of 5 minutes at useR!2017. You can listen to me in action there. I should have chosen a longer talk to explain more about this package, maybe next time. I will use this post to give you a more detailed version of the talk I gave in Brussels. Motivation behind bigstatsr I’m a PhD student in predictive human genetics. I’m basically trying to predict someone’s risk of disease based on their DNA mutations. These DNA mutations are ... Read More

Feed: James Serra's Blog. Author: James Serra. Azure SQL Data Sync has been ignored for quite some time, but has finally gotten an update (it’s in public preview).  This release includes several major improvements to the service including new Azure portal support, PowerShell and REST API support, and enhancements to security and privacy. SQL Azure Data Sync is a Microsoft Windows Azure web service that provides data synchronization capabilities for SQL databases.  SQL Azure Data Sync allows data to be synchronized between on-premises SQL Server databases and Azure SQL databases; in addition, it can also keep multiple Azure SQL databases ... Read More

Feed: R-bloggers. Author: That’s so Random. Virtually every dataset has them; id variables that link a record to a subject and/or time point. Often one column, or a combination of columns, forms the unique id of a record. For instance, the combination of patient_id and visit_id, or ip_adress and visit_time. The first step in most of my analyses is almost always checking the uniqueness of a variable, or a combination of variables. If it is not unique, may assumptions about the data may be wrong, or there are data quality issues. Since I do this so often, I decided to ... Read More

Feed: Hadoop – Cloudera Engineering Blog. Author: Justin Kestelyn. One of the first questions Cloudera customers raise when getting started with Apache Hadoop is how to select appropriate hardware for their new Hadoop clusters. Although Hadoop is designed to run on industry-standard hardware, recommending an ideal cluster configuration is not as easy as delivering a list of hardware specifications. Selecting hardware that provides the best balance of performance and economy for a given workload requires testing and validation. (For example, users with IO-intensive workloads will invest in more spindles per core.) In this blog post, you’ll learn some of the ... Read More

Feed: Hadoop – Cloudera Engineering Blog. Author: Justin Kestelyn. We’re very happy to re-publish the following post from Twitter analytics infrastructure engineering manager Dmitriy Ryaboy (@squarecog). In March we announced the Parquet project, the result of a collaboration between Twitter and Cloudera intended to create an open-source columnar storage format library for Apache Hadoop. Today, we’re happy to tell you about a significant Parquet milestone: a 1.0 release, which includes major features and improvements made since the initial announcement. But first, we’ll revisit why columnar storage is so important for the Hadoop ecosystem. What is Parquet and Columnar Storage? Parquet is an ... Read More