Sub setting times out of time series in R - r

Question

I downloaded stock market data from Yahoo (code below) - for context, at first I tried with getSymbols(^DJI) but I got error messages possibly related to Yahoo... different issue.
The point is that once downloaded, and imported into R, I massaged it into a format close enough to a time series to be able to run chartSeries(DJI):
require(RCurl)
require(foreign)
x <- getURL("https://raw.githubusercontent.com/RInterested/datasets/gh-pages/%5EDJI.csv")
DJI <- read.csv(text = x, sep =",")
DJI$Date <- as.Date(DJI$Date, format = "%m/%d/%Y") # Formatting Date as.Date
rownames(DJI) <- DJI$Date # Assigning Date to row names
DJI$Date <- NULL # Removing the Date column
chartSeries(DJI, type="auto", theme=chartTheme('white'))
even if the dataset is not really a time series:
> is.ts(DJI)
[1] FALSE
The problem comes about when I try to find out the date of, for instance, the minimum closing value of the Dow. I can do something like
> DJI[DJI$Close == min(DJI$Close),]
Open High Low Close Adj.Close Volume
1985-05-01 1257.18 1262.81 1239.07 1242.05 1242.05 10050000
yielding the entire row, including the row name (1985-05-01), which is the only part I want. However, if I insist on just getting the actual date, I have to juggle a second dataset containing the dates in one of the columns:
require(RCurl)
require(foreign)
x <- getURL("https://raw.githubusercontent.com/RInterested/datasets/gh-pages/%5EDJI.csv")
DJI <- read.csv(text = x, sep =",")
DJI$Date <- as.Date(DJI$Date, format = "%m/%d/%Y") # Formatting Date as.Date
rownames(DJI) <- DJI$Date # Assigning Date to row names
DJI.raw <- DJI # Second dataset for future subsetting
DJI$Date <- NULL # Removing the Date column
which does allow me to run
> DJI.raw$Date[DJI.raw$Close == min(DJI.raw$Close)]
[1] "1985-05-01"
Further, I don't think that turning the dataset into an .xts file would help.

Answer 1

I'm not clear what you want but it sounds like you just want the date? You mention xts is not an option (which would have been runnable)
time(as.xts(DJI))[which.min(DJI$Close)] # POSIXct format
# [1] "1985-05-01 EDT"
Otherwise a simple rownames + which.min would get the date for you?
as.Date(rownames(DJI)[which.min(DJI$Close)]) # Date format
# [1] "1985-05-01"