postgresql 日期显示为数字
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Date shows up as number
提问by MortenSickel
I have fetched a set of dates from postgresql, they look correct:
我从 postgresql 中获取了一组日期，它们看起来是正确的：
[1] "2007-07-13" "2007-07-14" "2007-07-22" "2007-07-23" "2007-07-24"
[6] "2007-07-25" "2007-08-13" "2007-08-14" "2007-08-15" "2007-08-16"
etc.
Then I want to run a loop on them to make new sql sentences to fetch some other data sets (yes, I know what I am doing, it would not have been possible to do all the processing in the database server)
然后我想对它们运行一个循环来创建新的 sql 语句来获取其他一些数据集（是的，我知道我在做什么，不可能在数据库服务器中进行所有处理）
So I tried
所以我试过了
for(date in geilodates)
mapdate(date,geilo)
Error in postgresqlExecStatement(conn, statement, ...) :
RS-DBI driver: (could not Retrieve the result : ERROR: invalid input syntax for type date: "13707"
LINE 1: ...id_date_location where not cowid is null and date='13707' or...
mapdate is a function I have written, the use of date within that is
mapdate 是我写的一个函数，里面日期的使用是
sql=paste('select * from gps_coord where cowid=',cowid," and date='",date,"'",sep='')
So, what has happened is that R silently converted my formatted dates to their integer representations before i tried to paste the sql together.
所以，发生的事情是在我尝试将 sql 粘贴在一起之前，R 默默地将我的格式化日期转换为它们的整数表示。
How do I get the original textual representation of the date? I tried
如何获得日期的原始文本表示？我试过
for(date in geilodates){
d=as.Date(date,origin="1970-01-01")
mapdate(d,geilo)
}
Error in charToDate(x) :
character string is not in a standard unambiguous format
And I have not managed to find any other functions to create a datestring (or to "serve" the date as the string I get when listing the variable
而且我还没有找到任何其他函数来创建日期字符串（或将日期“提供”为我在列出变量时得到的字符串
回答by wush978
try ?format.Date
尝试 ?format.Date
x <- Sys.Date()
class(x)
class(format(x))
In R, the data of class Dateis a numeric type.
An official way to represent Dateas string is to call format.
在 R 中，类的数据Date是数字类型。表示Date为字符串的官方方法是调用format.
I doubt that the format of dateis defined in your case, so pastedoes something unexpected.
我怀疑date在你的情况下定义了格式，所以paste有一些意想不到的事情。
Maybe you need to put format(x, "%Y-%m-%d")in your pastefunction instead of dateto tell R how which format you want for Date.
也许你需要format(x, "%Y-%m-%d")输入你的paste函数而不是date告诉 R 你想要日期的格式。
回答by MortenSickel
Thanks to wush978 for pointing me in the right direction, In the end I had to do:
感谢 wush978 为我指明了正确的方向，最后我不得不这样做：
for(d in geilodates){
date=format(as.Date(d,origin="1970-01-01"))
mapdate(date,geilo)
}
For some reason, inside the loop the "date" variable was seen as an integer, so I explicitely had to convert it to a date and then format it...
出于某种原因，在循环内部，“日期”变量被视为一个整数，因此我必须明确地将其转换为日期，然后对其进行格式化...
