10.12.2015, 20:13
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#8
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Регистрация: 22.07.2010
Адрес: Санкт-Петербург
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caty-zharr, рекомендую глянуть http://www.jstatsoft.org/article/view/v059i10
Цитата:
Tidy data is a standard way of mapping the meaning of a dataset to its structure. A dataset is
messy or tidy depending on how rows, columns and tables are matched up with observations,
variables and types. In tidy data:
1. Each variable forms a column.
2. Each observation forms a row.
3. Each type of observational unit forms a table.
This is Codd’s 3rd normal form (Codd 1990)
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