Column header in XTS and Data frame in R

External question — Data Science Stack Exchange Author: Balasubrahmanyam Ira Original post: https://datascience.stackexchange.com/questions/46003 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. I used quandl function extract stock data with object type as xts . a <- Quandl("NSE/ICICIBANK", start_date = "2011-01-01", end_date = "2019-02-21", collapse = "daily", type = "xts",order = "asc") then I printed the output a with head(a) , the output is Open High Low Last Close Total Trade Quantity Turnover (Lacs) 2011-01-03 1154.00 1158.40 1138.95 1140.35 1144.85 1379646 15845.58 2011-01-04 1145.70 1149.20 1098.10 1107.25 1104.05 4175490 46519.73 2011-01-05 1097.20 1099.00 1065.00 1068.80 1069.35 5307600 57075.28 2011-01-06 1074.25 1078.45 1047.25 1050.00 1053.45 4769781 50447.94 2011-01-07 1045.00 1077.90 1041.00 1042.00 1049.20 6178882 65700.46 2011-01-10 1044.25 1058.85 1005.10 1012.05 1014.00 6510410 67029.00 then I did the same without the object type as xts , the output of head(a) : Date Open High Low Last Close Total Trade Quantity Turnover (Lacs) 1 2011-01-03 1154.00 1158.40 1138.95 1140.35 1144.85 1379646 15845.58 2 2011-01-04 1145.70 1149.20 1098.10 1107.25 1104.05 4175490 46519.73 3 2011-01-05 1097.20 1099.00 1065.00 1068.80 1069.35 5307600 57075.28 4 2011-01-06 1074.25 1078.45 1047.25 1050.00 1053.45 4769781 50447.94 5 2011-01-07 1045.00 1077.90 1041.00 1042.00 1049.20 6178882 65700.46 6 2011-01-10 1044.25 1058.85 1005.10 1012.05 1014.00 6510410 67029.00 Why the date column field heading is missed out in xts object type but in data frame date field column heading is appearing? How to handle the same in xts object type?

External answer — Data Science Stack Exchange Author: knb Original post: https://datascience.stackexchange.com/a/46381 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. Because an R xts object stores the date-column in a special column called index , and the programmers who implemented the xts package have decided to not print a label such as "Date" in the table header of an xts output. When the print() method is called with an xts object as argument, the first column of the output is actually printed without any label, like a rowname "column" of a data frame. Why? I don't know. Perhaps "Date" is not always right. It could just be a different label that your time series needs (e.g. "Microseconds" for some timeseries object of Sensor measurements) # returned as data frame by Quandl R> str(a) 'data.frame': 1985 obs. of 8 variables: $ Date : Date, format: "2011-01-03" "2011-01-04" "2011-01-05" "2011-01-06" ... $ Open : num 1154 1146 1097 1074 1045 ... $ High : num 1158 1149 1099 1078 1078 ... $ Low : num 1139 1098 1065 1047 1041 ... $ Last : num 1140 1107 1069 1050 1042 ... $ Close : num 1145 1104 1069 1053 1049 ... $ Total Trade Quantity: num 1379646 4175490 5307600 4769781 6178882 ... $ Turnover (Lacs) : num 15846 46520 57075 50448 65700 ... - attr(*, "freq")= chr "daily" # returned as xts timeseries object R> str(ax) An ‘xts’ object on 2011-01-03/2019-01-04 containing: Data: num [1:1985, 1:7] 1154 1146 1097 1074 1045 ... - attr(*, "dimnames")=List of 2 ..$ : NULL ..$ : chr [1:7] "Open" "High" "Low" "Last" ... Indexed by objects of class: [Date] TZ: UTC xts Attributes: NULL