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POSIXctãªæ™‚刻データã«as.Dateã™ã‚‹ã¨ã€1æ—¥å‰ã®æ—¥ä»˜ã«å¤‰ã‚ã£ã¦ã—ã¾ã†ã€‚ > as.POSIXct("2001-01-01 00:00:01") [1] "2001-01-01 00:00:01 JST" > as.Date(as.POSIXct("2001-01-01 00:00:01")) [1] "2000-12-31" ã“ã‚Œã¯ã‚¿ã‚¤ãƒ ゾーンを指定ã—ãªã„ã¨GMTã¨è§£é‡ˆã•ã‚Œâ€¦
