I am using the QuantTools package in R language
When get_finam_data () is used, how can I obtain a list of symbols that can be acquired?
You should go to package internals to get the list.
Just download data for arbitrary symbol so the list is fetched from Finam server and saved for later use.
Keep in mind this is not documented so it can be changed in future versions.
get_finam_data( 'GAZP', Sys.Date() )
QuantTools:::finam_downloader_env$instruments_info
I suppose there no way to get it from QuantTools package. You can get it from https://www.finam.ru/profile/moex-akcii/mosenrg/export/?market=1 by hand or use external web sources.
Related
In my work I develop R packages that export R data objects (.RData). The name of these .RData files is always the same (e.g. files.RData). These packages also define and export a function that uploads the data to my database, say upload_data(). Inside upload_data() I first load the data using data(files, package = "PACKAGE NAME") and then push it into my database.
Let's say I have two packages, package1 and package2, which live on my file system. Given a vector of the package names (c("package1", "package2")), how would I go about to call 'upload_data()' programatically? Specifically, inside a script, how would I construct a call using "::" notation that constructs and evaluates a call like this: package1::upload_data()). I tried 'call' but couldn't get it right.
You could go the route of constructing the call using :: notation and evaluating that - but it's probably just easier to directly use get and specify the package you want to grab from.
get("upload_data", envir = asNamespace("package1"))
will return the function the same as using package1::upload_data would but is much easier to deal with programatically.
I am fairly new to R, but the more use it, the more I see how powerful it really is over SAS or SPSS. Just one of the major benefits, as I see them, is the ability to get and analyze data from the web. I imagine this is possible (and maybe even straightforward), but I am looking to parse JSON data that is publicly available on the web. I am not a programmer by any stretch, so any help and instruction you can provide will be greatly appreciated. Even if you point me to a basic working example, I probably can work through it.
RJSONIO from Omegahat is another package which provides facilities for reading and writing data in JSON format.
rjson does not use S4/S3 methods and so is not readily extensible, but still useful. Unfortunately, it does not used vectorized operations and so is too slow for non-trivial data. Similarly, for reading JSON data into R, it is somewhat slow and so does not scale to large data, should this be an issue.
Update (new Package 2013-12-03):
jsonlite: This package is a fork of the RJSONIO package. It builds on the parser from RJSONIO but implements a different mapping between R objects and JSON strings. The C code in this package is mostly from the RJSONIO Package, the R code has been rewritten from scratch. In addition to drop-in replacements for fromJSON and toJSON, the package has functions to serialize objects. Furthermore, the package contains a lot of unit tests to make sure that all edge cases are encoded and decoded consistently for use with dynamic data in systems and applications.
The jsonlite package is easy to use and tries to convert json into data frames.
Example:
library(jsonlite)
# url with some information about project in Andalussia
url <- 'https://api.stackexchange.com/2.2/badges?order=desc&sort=rank&site=stackoverflow'
# read url and convert to data.frame
document <- fromJSON(txt=url)
Here is the missing example
library(rjson)
url <- 'http://someurl/data.json'
document <- fromJSON(file=url, method='C')
The function fromJSON() in RJSONIO, rjson and jsonlite don't return a simple 2D data.frame for complex nested json objects.
To overcome this you can use tidyjson. It takes in a json and always returns a data.frame. It is currently not availble in CRAN, you can get it here: https://github.com/sailthru/tidyjson
Update: tidyjson is now available in cran, you can install it directly using install.packages("tidyjson")
For the record, rjson and RJSONIO do change the file type, but they don't really parse per se. For instance, I receive ugly MongoDB data in JSON format, convert it with rjson or RJSONIO, then use unlist and tons of manual correction to actually parse it into a usable matrix.
Try below code using RJSONIO in console
library(RJSONIO)
library(RCurl)
json_file = getURL("https://raw.githubusercontent.com/isrini/SI_IS607/master/books.json")
json_file2 = RJSONIO::fromJSON(json_file)
head(json_file2)
I am writing a function that will take the name of an installed package and return a data frame listing all the data frames available in that package along with the number and types of variables in those data frames.
In order to do this, I need to require the package temporarily so I can access its data sets. The problem I have is that requiring a package also introduces a whole lot of extra stuff into the search path and the loaded namespaces beyond just the package in question. I want my function to tidy up after itself, but I can't find a good way to detach everything that got imported when the package was required. In particular, detach seems to detach only the package, but not any of the other imported stuff.
Any advice?
I'm not sure what IDE you are workign with but many of them have "tab-completion". If I type :....... ?unload at my console and hit <tab> I immmediately see ??unloadNamespace ... so that would be a reasonable function to investigate. You should first look at:
?unloadNamespace
... and then decide if that is sufficient. There is also the detach function that has a link to its associated help page in that help page.
I'm working on an R package and (in the package's code) need to determine the version number when a certain function is called.
packageVersion("mypackage") works, but I'd rather not hard code the name of the package. How can I ask "what's the name of the package I'm in"? (Or directly get the version number of the package I'm in.)
This mailing list thread describes packageName().
(As Martin pointed out in comments.)
I have not handled working with packages. But I am assuming you can use something like
packageVersion(getPackageName())
While you can supply parameters to getPackageName to search for the package name you are looking for, I think just supplying it without any parameters will get the current environment, (and in your case) the current package.
Source:
The R Reference Index, available at https://cran.r-project.org/manuals.html
I am making an R package, and there is a need to keep track of files that were opened using the functions in the package.
What is the recommended procedure for creating R objects (in this case, a data.frame) upon loading the package in a way that is (sufficiently) hidden from the user? I do not want the user to manually edit the data.frame.
One idea I had was to create a data.frame in the options settings inside of an .onLoad call (similar to what Hadley does in his devtools package here), but the list of opened files is not really a configurable "option" in my package. Is there another way?
When you create an R package, unless you're exporting all objects, you have to list which objects are exported in the NAMESPACE file. If you need to maintain a data frame within your package but you don't want it made available to the user, you can choose not to export it by excluding it from the list.