[R] Advice on plotting a factor and displaying missing levels

[obradoa]

Great, this would work. Is it also possible to plot zero values for each
missing day, so when I do the line graph it properly drops to 0 if there was
no data for that day? Currently the line graph connects dots that represent
days with data present, but the line graph never drops to 0. I'd appreciate
if you have any suggestions for this. 

Thanks for you,

Alex


Gabor Grothendieck wrote:
> 
> Tabulate using table(), convert the dates to Date class and plot:
> 
> f <- factor(c("10/17/07", "10/17/07", "10/17/07", "10/17/07", "10/17/07",
> "10/17/07", "01/09/08", "01/17/08", "01/17/08", "01/17/08"))
> 
> ndays <- table(f)
> plot(as.Date(names(ndays), "%m/%d/%y"), ndays)
> 
>> I am trying to plot how many records are inserted into a database on a
>> certain date, but also represent days where no records are inserted. I
>> can
>> get a list of dates for inserted records using RMySQL
>>
>> result <- dbSendQuery(con, "select date_format(creation_ts, "%m/%d/%y")
>> from
>> mytable;")
>> inserts<-fetch(res2, n=-1)
>> >inserts
>>    created
>> 1  10/17/07
>> 2  10/17/07
>> 3  10/17/07
>> 4  10/17/07
>> 5  10/17/07
>> 6  10/17/07
>> 7  01/09/08
>> 8  01/17/08
>> 9  01/17/08
>> 10 01/17/08
>>
>>
>> When I factor the "created" date column I get the following:
>> > fcreated
>>  [1] 10/17/07 10/17/07 10/17/07 10/17/07 10/17/07 10/17/07 01/09/08
>> 01/17/08
>>  [9] 01/17/08 01/17/08
>> Levels: 01/09/08 01/17/08 10/17/07
>>
>> Then I plot the factor
>>
>> plot(fcreated)
>>
>> The graph looks correct and I see how many records I have on which date.
>>
>> However, I need also to see dates where no records were found in the
>> database. So instead of having 3 levels 01/09/08 01/17/08 10/17/07, I
>> need
>> to have the entire range of dates present on the graph starting with the
>> earliest date and finishing with the latest date. (For instance 10/17/07,
>> 10/18/07.... up to the latest date 1/9/08.) Y axis values for those dates
>> should be 0, except for values tabulated in my factor variable
>> "fcreated".
> 
> 

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