That said, I have two issues to ask for help with:
1) how to ignore cert errors with a fromJSON call
And
2) why the json data from the example link doesn't convert to a data frame. As
seen in the following example
library("rjson")
result <- fromJSON(file =
"https://www.semantic-mediawiki.org/w/api.php?action=ask&query=[[Category:City]]|?Capital%20of|?Has%20area&format=json")
json_data_frame <- as.data.frame(result)
print(json_data_frame)
which results in:
> library("rjson")
Warning message:
package ‘rjson’ was built under R version 3.4.4
> result <- fromJSON(file =
> "https://www.semantic-mediawiki.org/w/api.php?action=ask&query=[[Category:City]]|?Capital%20of|?Has%20area&format=json")
> json_data_frame <- as.data.frame(result)
Error in (function (..., row.names = NULL, check.rows = FALSE, check.names =
TRUE, :
arguments imply differing number of rows: 0, 1
> print(json_data_frame)
Error in print(json_data_frame) : object 'json_data_frame' not found
>
-----Original Message-----
From: R-help [mailto:[email protected]] On Behalf Of Evans, Richard
K. (GRC-H000)
Sent: Tuesday, May 08, 2018 11:52 AM
To: David Winsemius
Cc: [email protected]
Subject: Re: [R] help with json data from the web into data frame in R
Right. I'm trying to access a server within my organization which has a cert
error that I cannot fix.
The example link I provided was to a site on the web that does not have the
cert error.
From the linux shell I use the "-k" switch with cURL to ignore cert errors.. is
there an equivalent in the R world?
-Rich
-----Original Message-----
From: David Winsemius [mailto:[email protected]]
Sent: Tuesday, May 08, 2018 11:48 AM
To: Evans, Richard K. (GRC-H000)
Cc: Eric Berger; [email protected]
Subject: Re: [R] help with json data from the web into data frame in R
> On May 8, 2018, at 8:36 AM, Evans, Richard K. (GRC-H000)
> <[email protected]> wrote:
>
> I’ve been tinkering and discovered that the link I need to read json data
> from is ‘https’ and there is a certificate warning that I have to click
> through from a browser. That might be my issue. Is there any way in the json
> package to tell it to ignore self-signed cert errors in a url?
I didn't have that issue when using the link you offered:
library(jsonlite)
myJSON <- fromJSON(
url("https://www.semantic-mediawiki.org/w/api.php?action=ask&query=%5B%5BCategory:City%5D%5D&format=json";)
)
# results in a complex list (not trivially reducible to a dataframe:
str(myJSON)
List of 1
$ query:List of 5
..$ printrequests:'data.frame': 1 obs. of 5 variables:
.. ..$ label : chr ""
.. ..$ key : chr ""
.. ..$ redi : chr ""
.. ..$ typeid: chr "_wpg"
.. ..$ mode : int 2
..$ results :List of 39
.. ..$ File:2166320938 5cfc9ec72a z.jpg :List of 6
.. .. ..$ printouts : list()
.. .. ..$ fulltext : chr "File:2166320938 5cfc9ec72a z.jpg"
.. .. ..$ fullurl : chr
"https://www.semantic-mediawiki.org/wiki/File:2166320938_5cfc9ec72a_z.jpg";
#-----trimmed-----------
David
>
> -Rich
>
> From: Eric Berger [mailto:[email protected]]
> Sent: Tuesday, May 08, 2018 11:31 AM
> To: Evans, Richard K. (GRC-H000)
> Cc: [email protected]
> Subject: Re: [R] help with json data from the web into data frame in R
>
> Hi Rich,
> Take a look at the function fromJSON found in the rjson package.
> Note that the Usage in the help page: ?fromJSON names the second
> argument 'file' but if you look at the description the argument can be a URL.
>
> HTH,
> Eric
>
>
> On Tue, May 8, 2018 at 6:16 PM, Evans, Richard K. (GRC-H000)
> <[email protected]<mailto:[email protected]>> wrote:
> Hello
>
> I am able to construct a url that points to some data online in the JSON
> format. See an example at [0].
>
> I would like to work with this data as a dataframe in R.
>
> I know that there is a package for handling json data [1] but it assumes the
> data is in a local file but It is not clear to me how to request the data
> from the web in an R script and get the json data converted into a data frame
> in R.
>
> Can anyone provide a basic example or some guidance please?
>
> -Rich (revansx)
>
> [0]
> https://www.semantic-mediawiki.org/w/api.php?action=ask&query=[[Catego
> ry:City]]&format=json<https://www.semantic-mediawiki.org/w/api.php?act
> ion=ask&query=%5b%5bCategory:City%5d%5d&format=json>
> [1] https://www.tutorialspoint.com/r/r_json_files.htm
>
> ______________________________________________
> [email protected]<mailto:[email protected]> mailing list -- To
> UNSUBSCRIBE and more, see 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.
>
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> [email protected] mailing list -- To UNSUBSCRIBE and more, see
> 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
Alameda, CA, USA
'Any technology distinguishable from magic is insufficiently advanced.'
-Gehm's Corollary to Clarke's Third Law
______________________________________________
[email protected] mailing list -- To UNSUBSCRIBE and more, see
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.
______________________________________________
[email protected] mailing list -- To UNSUBSCRIBE and more, see
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.
![https://www.semantic-mediawiki.org/wiki/File:2166320938_5cfc9ec72a_z.jpg"](https://www.semantic-mediawiki.org/wiki/File:2166320938_5cfc9ec72a_z.jpg"){kind=link}