Q:

plot multiple columns in R

My data looks like,
HostName,iops,port_No,tag1,tag2,timestamp(epochTime)
Hostx,12,ab1,tag1,tag2,ts1
Hostx,20,ab1,tag1,tag2,ts2
Hostx,100,ab1,tag1,tag2,ts3
Hostx,32,abcd,tag1,tag2,ts1
Hostx,52,abcd,tag1,tag2,ts2
Hostx,62,abcd,tag1,tag2,ts3

I want to plot iops on y axis,timestamp on x-axis, & port_No as line(different colour) .
Also convert epoch time to currentdate.
Thanks

A:

Following works:
> 
> ddf
  HostName iops port_No tag1 tag2 timestamp
1    Hostx   12     ab1 tag1 tag2       ts1
2    Hostx   20     ab1 tag1 tag2       ts2
3    Hostx  100     ab1 tag1 tag2       ts3
4    Hostx   32    abcd tag1 tag2       ts1
5    Hostx   52    abcd tag1 tag2       ts2
6    Hostx   62    abcd tag1 tag2       ts3
> 
> 
> dput(ddf)
structure(list(HostName = structure(c(1L, 1L, 1L, 1L, 1L, 1L), .Label = "Hostx", class = "factor"), 
    iops = c(12L, 20L, 100L, 32L, 52L, 62L), port_No = structure(c(1L, 
    1L, 1L, 2L, 2L, 2L), .Label = c("ab1", "abcd"), class = "factor"), 
    tag1 = structure(c(1L, 1L, 1L, 1L, 1L, 1L), .Label = "tag1", class = "factor"), 
    tag2 = structure(c(1L, 1L, 1L, 1L, 1L, 1L), .Label = "tag2", class = "factor"), 
    timestamp = structure(c(1L, 2L, 3L, 1L, 2L, 3L), .Label = c("ts1", 
    "ts2", "ts3"), class = "factor")), .Names = c("HostName", 
"iops", "port_No", "tag1", "tag2", "timestamp"), class = "data.frame", row.names = c(NA, 
-6L))
> 
> ggplot(ddf,aes(y=iops, x=timestamp, group=port_No, color=port_No))+ geom_line()
> 

