张楠 开发者_StackOverflow中文版2021-05-17 18:13 单身女人可以接受全世界男人的追求刘飞
I\'m pretty new to Stata. I have a set of observation开发者_运维技巧s of the form \"CountryGDPYear\". I want to create a new variable GDP1960, which gives the GDP in 1960 of each country for each yea
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