[R] Automatic creation of columns in zoo object

[Gabor Grothendieck]

Not sure why you need to have all these extra columns if they are only
zero anyways.  Could you not append them when you get data for them?
Are these placeholders really of any value?  At any rate its done using
cbind or merge like this:

library(zoo)
library(chron)

nms <- sub(".Comdty", "tr", me.la.tickers)
zeromat <- matrix(0, nrow(me.la), length(nms), dimnames = list(NULL, nms))
cbind(me.la, zeromat)

In this case zeromat and me.la have the same dimensions so we could
alternately reduce it to this slightly briefer code:

zeromat <- 0 * me.la
colnames(zeromat) <- sub(".Comdty", "tr", me.la.tickers)
cbind(me.la, zeromat)


On Tue, Feb 3, 2009 at 8:44 AM, Sergey Goriatchev <sergeyg at gmail.com> wrote:
> Hello, everyone
>
> I have a question.
>
> Assume I have the following zoo object:
>
> me.la <- structure(c(1524.75, 1554.5, 1532.25, 1587.5, 1575.25, 1535.5,
> 1550, 1493.5, 1492.5, 1472.25, 1457.5, 1442.75, 1399, 1535.75,
> 1565.25, 1543.5, 1598.5, 1586.5, 1547, 1561.5, 1504.75, 1503.75,
> 1483.75, 1468.75, 1453.75, 1410, 1546.75, 1575.25, 1554, 1609,
> 1597.5, 1558.5, 1573, 1516.25, 1515.5, 1495, 1480, 1465, 1421.25,
> 1561.5, 1590, 1568.75, 1623.5, 1612, 1573, 1587.5, 1530.5, 1530,
> 1509.75, 1494.5, 1479.5, 1435.75, 1573.5, 1601.5, 1580.25, 1635,
> 1623.5, 1584.5, 1599, 1541.75, 1541.5, 1521.5, 1506, 1491, 1447.25,
> 1585.5, 1613, 1591.75, 1646, 1634.5, 1595.5, 1610, 1552.75, 1552.75,
> 1532.75, 1517, 1502, 1458.25, 1600, 1627.5, 1606.5, 1660, 1649,
> 1609.75, 1624.25, 1567, 1567, 1547, 1531, 1516, 1472.25, 1612,
> 1639.5, 1618.25, 1671.5, 1661, 1621.5, 1635.75, 1578, 1578, 1558,
> 1542, 1527, 1483.5), .Dim = c(13L, 8L), index = structure(c(14245,
> 14246, 14249, 14250, 14251, 14252, 14253, 14256, 14257, 14258,
> 14259, 14260, 14263), format = "m/d/y", origin = structure(c(1,
> 1, 1970), .Names = c("month", "day", "year")), class = c("dates",
> "times")), class = "zoo", .Dimnames = list(NULL, c("LA1 COMDTY",
> "LA2 COMDTY", "LA3 COMDTY", "LA4 COMDTY", "LA5 COMDTY", "LA6 COMDTY",
> "LA7 COMDTY", "LA8 COMDTY")))
>
> I also have a following variable (used in RBloomberg) in my environment:
>
> me.la.tickers <- c("LA1 Comdty", "LA2 Comdty", "LA3 Comdty", "LA4
> Comdty", "LA5 Comdty", "LA6 Comdty", "LA7 Comdty", "LA8 Comdty")
>
> What I need to do is to automate the following manual piece of code:
>
> me.la$LA2tr <- 0
> me.la$LA3tr <- 0
> me.la$LA4tr <- 0
> me.la$LA5tr <- 0
> me.la$LA6tr <- 0
> me.la$LA7tr <- 0
> me.la$LA8tr <- 0
>
> Basically, I need to automatically create new columns in futures
> object taking first part of names in me.la.tickers.
>
> I tried with paste() and assign() combination, but could not get.
>
> I could do the manual part, of course, it does not take much time, but:
>
> 1) I want to learn how to automatically create new columns in zoo objects
> 2) I have many more variables that have to be treated similarly (that
> is, I have me.lp with corresponding me.lp.tickers, me.qc with
> me.qc.tickers, etc. Then I have a bunch of variables starting with
> "en", like en.co and en.cl, and corresponding ticker vectors, then
> "ag" variables and "so" variables, as well). I have all in all 24 zoo
> variables with 24 corresponding ticker vectors, and for each a
> corresponding ticker vector, and for each zoo variable I need to
> create 7 extra columns. That would take much time to do manually, and
> a lot of code.
>
> How would I do this automatically, please?
>
> Thank you in advance for your help!
>
> Regards,
> Sergey
>
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