Rbind for appending zoo objects

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That is how rbind in the core of R works too and rbind.zoo works the same.

Try:

rbind(y1, y2[, colnames(y1)])
Hi R,

y1 <- zoo(matrix(1:10, ncol = 2), 1:5)

colnames(y1)=c("a","b")

y2 <- zoo(matrix(rnorm(10), ncol = 2), 6:10)

colnames(y2)=c("b","a")

y1
 a  b

1 1  6

2 2  7

3 3  8

4 4  9

5 5 10

y2
           b          a

6   0.9070204  0.3527630

7   1.2405943  0.8275001

8  -0.1690653 -0.1724976

9  -0.6905223 -1.1127670

10  0.3776210  0.4208908

Now, I have to append these two zoo objects, y1 and y2. So, I do as
follows:

rbind(y2,y1)
           b          a

1   1.0000000  6.0000000

2   2.0000000  7.0000000

3   3.0000000  8.0000000

4   4.0000000  9.0000000

5   5.0000000 10.0000000

6   0.9070204  0.3527630

7   1.2405943  0.8275001

8  -0.1690653 -0.1724976

9  -0.6905223 -1.1127670

10  0.3776210  0.4208908

The doubts I get are as follows:

1.      The above rbind function for the zoo objects doesn't take care
of the column names while merging. Example: Column 'a' of y1 is appended
with column 'b' of y2. Why is this so? How do I get rid of this?
2.      In the rbind function, I have given y2 first and then y1. But in
the appended data, I see the data corresponding to y1 first and then of
y2. Is this because of ordering of the index elements of the zoo
objects?

Or, is there any other better function to append zoo objects?

Thanks in advance,

Shubha

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1.	The above rbind function for the zoo objects doesn't take care
of the column names while merging. Example: Column 'a' of y1 is appended
with column 'b' of y2. Why is this so?
We do not check the column names at all. This should probably be changed.
How do I get rid of this?
Sort the columns by hand before calling rbind().
2.	In the rbind function, I have given y2 first and then y1. But in
the appended data, I see the data corresponding to y1 first and then of
y2. Is this because of ordering of the index elements of the zoo
objects?
Yes, recall that the second "o" in "zoo" means "ordered".

Best,
Z