如何使用rbind将数据表与POSIXct和Date列类合并？
如何使用rbind将数据表与POSIXct和Date列类合并？
提问于 2015-03-31 13:02:11
我想合并两个数据表，但其中一个有列ddate和POSIXct类，另一个有列ddate和Date类。
我希望结果数据表有POSIXct类，但实际结果取决于传递给rbind的参数序列。
zz1 <- "or,d,ddate,rdate,changes,class,price,fdate,company,number,minutes,added,source
VA1,VA2,2014-05-24,,0,0,2124,2014-05-22 15:50:16,,,,2014-05-22 12:20:03,ss
VA1,VA2,2014-05-26,,0,0,2124,2014-05-22 15:03:44,,,,2014-05-22 12:20:03,s1
VA1,VA2,2014-06-05,,0,0,2124,2014-05-22 15:48:24,,,,2014-05-22 12:20:03,s1
VA1,VA2,2014-06-09,,0,0,2124,2014-05-22 15:37:35,,,,2014-05-22 12:20:03,s2
VA1,VA2,2014-06-16,,0,0,2124,2014-05-22 14:17:33,,,,2014-05-22 12:20:03,ss"
zz2 <- "or,d,ddate,rdate,changes,class,price,fdate,company,number,minutes,added,source
VA3,VA4,2014-05-24 12:23:00,,0,0,2124,2014-05-22 15:50:16,,,,2014-05-22 12:20:03,ss
VA1,VA2,2014-05-26 14:00:01,,0,0,2124,2014-05-22 15:03:44,,,,2014-05-22 12:20:03,s1
VA5,VA6,2014-06-05 18:00:04,,0,0,2124,2014-05-22 15:48:24,,,,2014-05-22 12:20:03,s1
VA7,VA8,2014-06-09 18:00:07,,0,0,2124,2014-05-22 15:37:35,,,,2014-05-22 12:20:03,s2
VA9,VA0,2014-06-16 19:00:20,,0,0,2124,2014-05-22 14:17:33,,,,2014-05-22 12:20:03,ss"
columnClasses <- c("factor", "factor", "Date", "factor", "integer", "factor", "integer", "factor", "factor", "factor", "integer", "factor", "factor")
dt1 <- read.table(text=zz1, header = TRUE, sep = ",", comment.char = "", quote = "", na.strings = c(""), colClasses = columnClasses)
columnClasses <- c("factor", "factor", "POSIXct", "factor", "integer", "factor", "integer", "factor", "factor", "factor", "integer", "factor", "factor")
dt2 <- read.table(text=zz2, header = TRUE, sep = ",", comment.char = "", quote = "", na.strings = c(""), colClasses = columnClasses)
dt <- rbind(dt1, dt2)
class(dt$ddate) # [1] "Date"
dt <- rbind(dt2, dt1)
class(dt$ddate) # [1] "POSIXct" "POSIXt"我应该怎么做才能永远拥有POSIXct？由于当我从CSV文件获得数据时无法控制序列，如下所示：
tables <- lapply(files, readCSVFile)
dt <- rbindlist(tables, fill = TRUE)回答 1
Stack Overflow用户
回答已采纳
发布于 2015-03-31 13:10:07
我认为您可以在使用read.csv加载每个文件时处理这些文件，以便将ddate变量转换为POSIXct。这样就可以更好地控制合并。这可以通过创建要由lapply使用的自己的函数来实现。
示例
ddate.convert = function(x){tmp <- readcsv(x); tmp$ddate <- as.POSIXct(tmp$ddate); tmp}
tables <- lapply(files, FUN=ddate.convert)
dt <- rbindlist(tables, fill = TRUE)页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/29369336
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