STATA学习笔记：数据合并

一 横向合并数据：merge

1. One-to-one merge on specified key variables

merge 1:1 varlist using filename [, options]
// 1:1 后面接合并时依据的“key”
//filename可以是数据地址，也可以是数据名称

例1

webuse autosize
list

webuse autoexpense
list

webuse autosize
merge 1:1 make using http://www.stata-press.com/data/r14/autoexpense
list

_merge列的值有三个:1,2,3
1代表该行数据仅仅来自于第一份dataset
2代表该行数据仅仅来自于第二份dataset
3代表该行数据既来自于第一份dataset又来自于第二份dataset

例2

cd "D:\STATA\STATA学习资料\LY_stata\_Data"
use merge_m.dta, clear
merge 1:1 date using merge_u.dta
br

2.Many-to-one merge on specified key variables

merge m:1 varlist using filename [, options]

例子

webuse dollars, clear
list

webuse sforce
list

webuse sforce,clear
merge m:1 region using http://www.stata-press.com/data/r14/dollars
list

添加选项nogen

webuse sforce,clear
merge m:1 region using "http://www.stata-press.com/data/r14/dollars",nogen
list

3.One-to-many merge on specified key variables

webuse dollars, clear
merge 1:m region using "http://www.stata-press.com/data/r14/sforce"
list

二 纵向合并数据 append

append using filename [filename ...] [, options]

例子

webuse even,clear
list

webuse odd,clear
list

webuse odd,clear
append using http://www.stata-press.com/data/r14/even
list