Q:

Nested loop output to a data.frame

I have two datasets in R (these tables below are just smaller versions) that I would like to combine into a new data frame.
> meetingtime2     
#two columns of datetime that class=factor

               ST                  ET
1 2014-12-22 07:00:00 2014-12-22 07:30:00
2 2014-12-22 07:30:00 2014-12-22 08:00:00
3 2014-12-22 08:00:00 2014-12-22 08:30:00
4 2014-12-22 08:30:00 2014-12-22 09:00:00
5 2014-12-22 09:00:00 2014-12-22 09:30:00

> roomdata2 
#three columns; Room=factor, Capacity=integer, Video Conference=numeric

   Room Capacity Video.Conference
1 0M02A       16                1
2 0M03A        8                0
3 0M03B       12                1

The desired output would be a 15 row by 5 column matrix. In easy speak the output is every time slot for every room. 
#the following is a MANUALLY created output of what the first few rows should look like

    Room Capacity Video.Conference        ST                ET
 1 0M02A   16           1       2014-12-22 07:00:00 2014-12-22 07:30:00
 2 0M02A   16           1       2014-12-22 07:30:00 2014-12-22 08:00:00
 3 0M02A   16           1       2014-12-22 08:00:00 2014-12-22 08:30:00
 4 0M02A   16           1       2014-12-22 08:30:00 2014-12-22 09:00:00
 5 0M02A   16           1       2014-12-22 09:00:00 2014-12-22 09:30:00
 6 0M03A   16           1       2014-12-22 07:00:00 2014-12-22 07:30:00
 7 0M03A   16           1       2014-12-22 07:30:00 2014-12-22 08:00:00
#and so forth to 15 rows. 

I've tried using a nested loop 
#note, the code is written so I can apply to a bigger (1000's of rows) dataset

 >mylist<-list() 
 >for(i in 1:(nrow(roomdata2)))   
   +{   for(j in 1:(nrow(meetingtime2)))   
 +mylist[[j]]<-      data.frame(roomdata2[i,1],roomdata2[i,2],roomdata2[i,3],
 +meetingtime2[j,1],meetingtime2[j,2])  
  } 
   >df<-do.call("rbind",mylist)  
>df 

The output I get. I'm getting all the timeslots for the last room, just not the preceding rooms
roomdata2.i..1. roomdata2.i..2. roomdata2.i..3.  meetingtime2.j..1.  meetingtime2.j..2.
1    0M03B          12             1         2014-12-22 07:00:00    2014-12-22 07:30:00
2    0M03B          12             1         2014-12-22 07:30:00    2014-12-22 08:00:00
3    0M03B          12             1         2014-12-22 08:00:00    2014-12-22 08:30:00
4    0M03B          12             1         2014-12-22 08:30:00    2014-12-22 09:00:00
5    0M03B          12             1         2014-12-22 09:00:00    2014-12-22 09:30:00

I know my code is far from correct and is giving me the final iteration of the loop.
The other way I looked at this was a continuous print function for each iteration
 >for(i in 1:(nrow(roomdata2))) 
 >for(j in 1:(nrow(meetingtime2))) 
 >print(paste(roomdata2[i,1],roomdata2[i,2],roomdata2[i,3],
 +meetingtime2[j,1],meetingtime2[j,2]))

the output
 [1] "0M02A 16 1 2014-12-22 07:00:00 2014-12-22 07:30:00"
 [1] "0M02A 16 1 2014-12-22 07:30:00 2014-12-22 08:00:00"
 [1] "0M02A 16 1 2014-12-22 08:00:00 2014-12-22 08:30:00"
 [1] "0M02A 16 1 2014-12-22 08:30:00 2014-12-22 09:00:00"
 [1] "0M02A 16 1 2014-12-22 09:00:00 2014-12-22 09:30:00"
 [1] "0M03A 8 0 2014-12-22 07:00:00 2014-12-22 07:30:00"
 [1] "0M03A 8 0 2014-12-22 07:30:00 2014-12-22 08:00:00"
 [1] "0M03A 8 0 2014-12-22 08:00:00 2014-12-22 08:30:00"
 [1] "0M03A 8 0 2014-12-22 08:30:00 2014-12-22 09:00:00"
 [1] "0M03A 8 0 2014-12-22 09:00:00 2014-12-22 09:30:00"
 [1] "0M03B 12 1 2014-12-22 07:00:00 2014-12-22 07:30:00"
 [1] "0M03B 12 1 2014-12-22 07:30:00 2014-12-22 08:00:00"
 [1] "0M03B 12 1 2014-12-22 08:00:00 2014-12-22 08:30:00"
 [1] "0M03B 12 1 2014-12-22 08:30:00 2014-12-22 09:00:00"
 [1] "0M03B 12 1 2014-12-22 09:00:00 2014-12-22 09:30:00"

#however the values are not separated, they are just in one set of string for each row.

The desired result is a table like directly above, but instead a dataframe with each value in a seperate column (each date & time set together in one column).
I've looked into lists,lapply,foreach but I just can't wrap my head around the solution.
Any help would be appreciated, I'm a beginner so I'm keen to learn.
Cheers
* the dputs
>dput(meetingtime2)

structure(list(ST = structure(1:5, .Label = c("22/12/2014 7:00", 
"22/12/2014 7:30", "22/12/2014 8:00", "22/12/2014 8:30", "22/12/2014 9:00"
), class = "factor"), ET = structure(1:5, .Label = c("22/12/2014 7:30", 
"22/12/2014 8:00", "22/12/2014 8:30", "22/12/2014 9:00", "22/12/2014 9:30"
), class = "factor")), .Names = c("ST", "ET"), row.names = c(NA, 
-5L), class = "data.frame")
>dput(roomdata2)

structure(list(Room = structure(1:3, .Label = c("0M02A", "0M03A", 
"0M03B"), class = "factor"), Capacity = c(16L, 8L, 12L), Video.Conference = c(1L, 
0L, 1L)), .Names = c("Room", "Capacity", "Video.Conference"), row.names = c(NA, 
-3L), class = "data.frame")

A:

Using your data:
meetingtime2 <- read.csv(text = "ST,ET
2014-12-22 07:00:00,2014-12-22 07:30:00
2014-12-22 07:30:00,2014-12-22 08:00:00
2014-12-22 08:00:00,2014-12-22 08:30:00
2014-12-22 08:30:00,2014-12-22 09:00:00
2014-12-22 09:00:00,2014-12-22 09:30:00")

roomdata2 <- read.csv(text = "Room,Capacity,Video_Conference
0M02A,16,1
0M03A,8,0
0M03B,12,1")

Then merge handily returns the Cartesian product, because none of the columns match.
merge(meetingtime2, roomdata2)[, c(3:5, 1:2)]

##     Room Capacity Video_Conference                  ST                  ET
## 1  0M02A       16                1 2014-12-22 07:00:00 2014-12-22 07:30:00
## 2  0M02A       16                1 2014-12-22 07:30:00 2014-12-22 08:00:00
## 3  0M02A       16                1 2014-12-22 08:00:00 2014-12-22 08:30:00
## 4  0M02A       16                1 2014-12-22 08:30:00 2014-12-22 09:00:00
## 5  0M02A       16                1 2014-12-22 09:00:00 2014-12-22 09:30:00

