Say I have data on people who choose between several options. I have one row per person, and I want to have one row per person and choice option. So, if I have 10 people who have 3 choices, right now I have 10 rows, and I want to have 30.Say I have data on people who choose between se
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如何使用tidyr填充分组变量的每个值中的已完成行？
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