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Working with Java plugins (Part 1)

Introduction

Three months ago, I wrote about a new command, twitter2stata, that imports data from Twitter’s REST API into Stata. Today, I will show you the tools we used to develop this command. Writing this command from scratch solely in Mata or ado-code would have taken several months. Fortunately, we can significantly speed up our development using an existing Java library (Twitter4J) and Stata’s Java plugins. In this post, I will discuss the basic steps of how to leverage a Java library and the Stata Java API.

Java is the most popular programming language in the world, so there are many libraries to support your development. A quick Google search should tell you if a Java library exists for what you are trying to do; this is how we found the library Twitter4J. For the rest of this blog entry, a basic understanding of programming in Java is helpful, but not necessary. Read more…

Categories: Programming Tags: , ,

Importing WRDS data into Stata

Wharton Research Data Services (WRDS) is a leading research platform and business intelligence tool for 400+ corporate, academic, and government researchers. If your institution subscribes to WRDS, you can now easily access WRDS data remotely via Stata’s odbc command. For questions or subscription information click here. Read more…

Importing Twitter data into Stata

In the past, we’ve had users ask if Stata could import Twitter data. So we asked one of our interns, Dawson Deere (currently working on his computer science degree at Texas A&M University) to see if he could write a new command to do this. He used Stata 15’s improved Java plugins feature to write a new twitter2stata command. To install twitter2stata, type

ssc install twitter2stata, replace

Read more…

Categories: Data Management Tags: ,

Retaining an Excel cell’s format when using putexcel

In a previous blog entry, I talked about the new Stata 13 command putexcel and how we could use putexcel with a Stata command’s stored results to create tables in an Excel file.

After the entry was posted, a few users pointed out two features they wanted added to putexcel:

  1. Retain a cell’s format after writing numeric data to it.
  2. Allow putexcel to format a cell.

In Stata 13.1, we added the new option keepcellformat to putexcel. This option retains a cell’s format after writing numeric data to it. keepcellformat is useful for people who want to automate the updating of a report or paper. Read more…

Categories: Programming Tags: , , , , ,

Export tables to Excel

There is a new command in Stata 13, putexcel, that allows you to easily export matrices, expressions, and stored results to an Excel file. Combining putexcel with a Stata command’s stored results allows you to create the table displayed in your Stata Results window in an Excel file. Read more…

Categories: Programming Tags: , , , ,

Using import excel with real world data

Stata 12’s new import excel command can help you easily import real-world Excel files into Stata. Excel files often contain header and footer information in the first few and last few rows of a sheet, and you may not want that information loaded. Also, the column labels used in the sheet are invalid Stata variable names and therefore cannot be loaded. Both of these issues can be easily solved using import excel. Read more…

Categories: Data Management Tags: ,

Building complicated expressions the easy way

Have you every wanted to make an “easy” calculation–say, after fitting a model–and gotten lost because you just weren’t sure where to find the degrees of freedom of the residual or the standard error of the coefficient? Have you ever been in the midst of constructing an “easy” calculation and was suddenly unsure just what e(df_r) really was? I have a solution.

It’s called Stata’s expression builder. You can get to it from the display dialog (Data->Other Utilities->Hand Calculator) Read more…

Categories: Statistics Tags: ,

Connection string support added to odbc command

Stata’s odbc command allows you to import data from and export data to any ODBC data source on your computer. ODBC is a standardized way for applications to read data from and write data to different data sources such as databases and spreadsheets.

Until now, before you could use the odbc command, you had to add a named data source (DSN) to the computer via the ODBC Data Source Administrator. If you did not have administrator privileges on your computer, you could not do this. Read more…