视频推荐：一文看懂Stata数据管理

来源：Stata Blog

原文：https://blog.stata.com/2017/11/15/data-management-made-easy/

Data management made easy

Data management and data cleaning are critically important steps in any data analysis. Many of us learned this lesson the hard way. Have you ever fit a model that includes age as a covariate and forgotten to convert the missing value codes of -99 to missing values? I have. Or maybe you overlooked a data entry error that resulted in an age of 354 that should have been 54. I’ve done that too. Careful data management and cleaning can help us avoid these kinds of embarrassing mistakes. 

I recently recorded a series of data management videos for the Stata Youtube Channel. You can click on the links below to watch the videos. I included topics that I think are important, but the list is far from exhaustive. If you would like to see videos on additional topics, please leave your suggestion in the comments below.

Data management playlist 

How to merge files into a single dataset（merge）

How to append files into a single dataset （append）

How to label variables （标签）

How to label the values of categorical variables （label）

How to add notes to a variable （note）

How to convert a string variable to a numeric variable （数据结构）

How to convert categorical string variables to labeled numeric variables （数值与字符型）

How to create a date variable from a date stored as a string （数据变量）

How to convert missing value codes to missing values 

How to identify and replace unusual data values 

How to round a continuous variable 

How to change the display format of a variable 

How to create a new variable that is calculated from other variables 

How to create a categorical variable from a continuous variable How to identify and remove duplicate observations 

How to reshape data from wide format to long format 

How to reshape data from long format to wide format 

How to optimize the storage of variables（存储）