[R] re move row if the column "date_abandoned" has a date in it

frenchcr frenchcr at btinternet.com
Sun Nov 15 19:56:38 CET 2009 


this works perfectly...

new_data5 <- new_data4[nchar(new_data4$date_abandoned) != 8, ]

...and i can now think of a few different ways to manipulate my data with
what ive learned from these tricks, thanks alot David!




David Winsemius wrote:
> 
> 
> On Nov 15, 2009, at 11:00 AM, frenchcr wrote:
> 
>>
>>
>> Yes they are not in date format, theyre just characters.
>>
>> the earliest date is 16010000 i originally had one of  0101 00 00  
>> (101 years
>> BC)...this was a software problem.
>>
>>> table(nchar(new_data4$date_abandoned))
>>
>>     2      8
>> 315732    263
>>
>> The 315732 are empty fields i thought.
> 
> They are actually 2 characters wide.
> 
>> The 263 are dates, i want to remove their rows.
> 
> If you want to "remove" the ones that are _not_ 8 characters long, then:
> 
> new_data5 <- new_data4[nchar(new_data4$date_abandoned) != 8, ]
> 
> or:
> 
> new_data5 <- subset(new_data4, date_abandoned != 8)
> 
> -- 
> David.
> 
>>
>>
>>
>> David Winsemius wrote:
>>>
>>>
>>> On Nov 14, 2009, at 8:43 PM, frenchcr wrote:
>>>
>>>>
>>>> sorry David,
>>>>
>>>> im really new to R (my first week) and appreciate your help. Also I
>>>> dont
>>>> always know what info to give people on the forum (although im
>>>> starting to
>>>> catch the drift).
>>>>
>>>> heres what i get...
>>>>
>>>> summary(new_data4$date_abandoned)
>>>> Min.        1st Qu.    Median     Mean      3rd Qu.
>>>> Max.          NA's
>>>> 16010000 19980000 20010000 19930000 20040000  20090000   315732
>>>
>>> So new_data4$data_abandoned is not of type "Date" and is instead a
>>> character vector.
>>>
>>> If you are resisting turning it into a date and want to work with
>>> characters, you can, you just need to deal somehow with the items  
>>> that
>>> are not 8 characters wide. What does 315732 represent? How were we
>>> supposed to interpret the starting "date" you gave of "01010000"?
>>>
>>>> nchar("1010000")
>>> [1] 7
>>>
>>> What does table(nchar(new_data4$date_abandoned)) give you?
>>>>
>>>>> ls()
>>>> [1] "data"      "new_data"  "new_data2" "new_data3" "new_data4"
>>>>> small <- head(new_data4, 20)
>>>>> dump("small", 20)
>>>> Error in dump("small", 20) : cannot write to this connection
>>>
>>>
>>> Well, sorry, I meant to type dump("small", stdout())   ... As per the
>>> Posting Guide.
>>>
>>> -- 
>>> David.
>>>>
>>>> David Winsemius wrote:
>>>>>
>>>>>
>>>>> On Nov 14, 2009, at 5:24 PM, frenchcr wrote:
>>>>>
>>>>>>
>>>>>>
>>>>>> I tried the following but it does the opposite of what i want:
>>>>>>
>>>>>> new_data5 <- subset(new_data4, date_abandoned > "01010000")
>>>>>>
>>>>>> I want to remove the rows with dates and leave just the rows  
>>>>>> without
>>>>>> a date.
>>>>>>
>>>>>> This removes all the rows that dont have a date in the
>>>>>> date_abandoned column
>>>>>>
>>>>>> ...on a positive note, as i did this next...
>>>>>>
>>>>>> dim(new_data5)
>>>>>> [1] 263  80
>>>>>>
>>>>>> ....i now know that i have 263 dates in that column :)
>>>>>>
>>>>>> I want to remove the 263 rows with dates and leave just the rows
>>>>>> without a
>>>>>> date.
>>>>>
>>>>> Con=me on frenchcr. Stop making us guess. Give us enough  
>>>>> information
>>>>> to work with. You asked for something which I construed as saying  
>>>>> you
>>>>> wanted dates greater than the the first day of the year 101. You  
>>>>> did
>>>>> not address this question.
>>>>>
>>>>> What do you get with str(new_data4) and
>>>>> summary(new_data4$date_abandoned) ? In order to know what sort of
>>>>> comparison to use we need to know what the data looks like.
>>>>>
>>>>> Even better if you offered the output from:
>>>>>
>>>>> small <- head(new_data4, 20)
>>>>> dump("small", 20),
>>>>>
>>>>> -- 
>>>>> David
>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> David Winsemius wrote:
>>>>>>>
>>>>>>>
>>>>>>> On Nov 14, 2009, at 1:21 PM, frenchcr wrote:
>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> I want to go through a column in data called
>>>>>>>
>>>>>>> Bad name for a data.frame. Fortunes, "dog" and all that.
>>>>>>>
>>>>>>>> date_abandoned....data["date_abandoned"]....and remove all the
>>>>>>>> rows
>>>>>>>> that
>>>>>>>> have numbers greater than 1,010,000.
>>>>>>>
>>>>>>> Are you doing archeology? Given what you say next I wondered what
>>>>>>> range you were really asking for.
>>>>>>>
>>>>>>>>
>>>>>>>> The dates are in the format 20091114 so i'm just going to treat
>>>>>>>> them
>>>>>>>> as
>>>>>>>> numbers for clean up purposes.
>>>>>>>>
>>>>>>>>
>>>>>>>> I know that i use subset but not sure how to proceed from there.
>>>>>>>
>>>>>>> subdata <- subset(data, date_abandoned > "01010000"()
>>>>>>>
>>>>>>>
>>>>>>> The problem with > "1010000" is that your specified minimum point
>>>>>>> had
>>>>>>> an insufficient number of "places" to be in YYYYMMDD format.
>>>>>>>
>>>>>>> --
>>>>>>>
>>>>>>> David Winsemius, MD
>>>>>>> Heritage Laboratories
>>>>>>> West Hartford, CT
>>>>>>>
>>>>>>> ______________________________________________
>>>>>>> R-help at r-project.org mailing list
>>>>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>>>>> PLEASE do read the posting guide
>>>>>>> http://www.R-project.org/posting-guide.html
>>>>>>> and provide commented, minimal, self-contained, reproducible  
>>>>>>> code.
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> -- 
>>>>>> View this message in context:
>>>>>> http://old.nabble.com/remove-row-if-the-column-%22date_abandoned%22-has-a-date-in-it-tp26352457p26354446.html
>>>>>> Sent from the R help mailing list archive at Nabble.com.
>>>>>>
>>>>>> ______________________________________________
>>>>>> R-help at r-project.org mailing list
>>>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>>>> PLEASE do read the posting guide
>>>>>> http://www.R-project.org/posting-guide.html
>>>>>> and provide commented, minimal, self-contained, reproducible code.
>>>>>
>>>>> David Winsemius, MD
>>>>> Heritage Laboratories
>>>>> West Hartford, CT
>>>>>
>>>>> ______________________________________________
>>>>> R-help at r-project.org mailing list
>>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>>> PLEASE do read the posting guide
>>>>> http://www.R-project.org/posting-guide.html
>>>>> and provide commented, minimal, self-contained, reproducible code.
>>>>>
>>>>>
>>>>
>>>> -- 
>>>> View this message in context:
>>>> http://old.nabble.com/remove-row-if-the-column-%22date_abandoned%22-has-a-date-in-it-tp26352457p26355689.html
>>>> Sent from the R help mailing list archive at Nabble.com.
>>>>
>>>> ______________________________________________
>>>> R-help at r-project.org mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>> PLEASE do read the posting guide
>>>> http://www.R-project.org/posting-guide.html
>>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>> David Winsemius, MD
>>> Heritage Laboratories
>>> West Hartford, CT
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide
>>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>>
>>
>> -- 
>> View this message in context:
>> http://old.nabble.com/remove-row-if-the-column-%22date_abandoned%22-has-a-date-in-it-tp26352457p26360384.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
> 
> David Winsemius, MD
> Heritage Laboratories
> West Hartford, CT
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 
> 

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