Question

我正在尝试将数据列从因素转换为日期格式，但总会出现一些问题。原始日期列如下所示：

date
1/01/2008
1/01/2008
1/01/2008
1/01/2008
1/01/2008

查看前6行

head(PowerConsumption)

它表明：

$ Date: Factor w/ 729 levels "1/01/2007","1/01/2008",..: 189 189 189 189 189 189 189 189 189 189 ...

不太明白所有这些189意味着什么？
我的意思是更改因果日期类型。

应用此代码后：

date <- as.Date(PowerConsumption$Date, format = "%d%m%Y")

所有值都变为NA。任何人都可以指出什么是错的吗？

Answer 1

首先，所有189表示向量以该因子变量的第189级值开始。一个简化的例子：

> x <- factor(c("1/01/2007","1/01/2008","1/01/2007","1/01/2008"))
> str(x)
 Factor w/ 2 levels "1/01/2007","1/01/2008": 1 2 1 2

其次，当您想将该日期变量转换为日期格式时，您需要指定原始变量的正确格式（在指定格式参数时省略了/）：

> as.Date(x, format="%d/%m/%Y")
[1] "2007-01-01" "2008-01-01" "2007-01-01" "2008-01-01"

与我在评论中所说的相反，这个因子变量不一定需要先用as.character转换为字符。

将因子值中心转换为日期的另一个选项是使用新anydate包中的anytime函数：

> library(anytime)
> anydate(x)
[1] "2007-01-01" "2008-01-01" "2007-01-01" "2008-01-01"

Answer 2

当然，有一个<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet" /> <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script> <div class="container-fluid page-top">  <button type="button" class="btn btn-info btn-lg" data-toggle="modal" data-target="#myModal">Open Modal</button> <div class="modal fade" id="myModal"> <div class="modal-dialog modal-lg"> <div class="modal-content"> <div class="form-horizontal" id="myForm" role="form"> <div class="modal-header"> <button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button> <h4 class="modal-title">My modal</h4> </div> <div class="modal-body"> <div class="form-group has-feedback"> <div class="col-lg-12"> <label class="control-label col-sm-3" for="tbTitle">Public Title:</label> <div class="input-group col-sm-5"> <input name="ctl00$cpMain$tbTitle" type="text" id="cpMain_tbTitle" class="form-control required" value="Basic Gold Program" /> </div> </div> </div> <div class="form-group has-feedback"> <div class="col-lg-12"> <label class="control-label col-sm-3" for="tbInternalTitle">Internal Title:</label> <div class="input-group col-sm-5"> <input name="ctl00$cpMain$tbInternalTitle" type="text" id="cpMain_tbInternalTitle" class="form-control required" value="BASEPLAN" /> </div> </div> </div> <div class="form-group has-feedback"> <div class="col-lg-12"> <label class="control-label col-sm-3" for="tbPrice">Monthly Price:</label> <div class="input-group col-sm-5"> <input name="ctl00$cpMain$tbPrice" type="text" id="cpMain_tbPrice" class="form-control required" value="$75.00" /> </div> </div> </div> </div> <div class="modal-footer"> <button type="button" class="btn btn-default" data-dismiss="modal">Close</button> </div> </div> </div> </div> </div>解决方案：

lubridate

使用R中的as.date转换日期因子

2 个答案: