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search for r(2000) (manual: [R] search)
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[P] error . . . . . . . . . . . . . . . . . . . . . . . . Return code 2000
no observations;
You have requested some statistical calculation and there are
no observations on which to perform it. Perhaps you specified
if or in and inadvertently filtered all the data.
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这是错误,求不沉