Create JSON to send API request in R - r

This might have been asked and solved before, I just can't get a straightforward answer.
I got the following:
text <- 'Testing to be translated'
Which I am trying to get into JSON format like:
[{"Text": "Testing to be translated"}]
I have tried using toJSON but I could not get that structure.
Additionally, I did some quick-fix:
paste0('[{"Text":"', text, '"}]')
Which would work fine; however, I have some strings with the " and ' characters in it and they would break this code.
Any input would be helpful.
More context: I am using a GET request to translate text from Azure server, could not use translateR so I am creating my own function.

To create an array, pass jsonlite::toJSON an unnamed list or vector. You should also set auto_unbox=TRUE so that scalars aren't treated as arrays.
text <- 'Testing to be translated'
jsonlite::toJSON(list(list(Text=text)), auto_unbox=TRUE)
# [{"Text":"Testing to be translated"}]

Related

How to pass a chr variable into r"(...)"?

I've seen that since 4.0.0, R supports raw strings using the syntax r"(...)". Thus, I could do:
r"(C:\THIS\IS\MY\PATH\TO\FILE.CSV)"
#> [1] "C:\\THIS\\IS\\MY\\PATH\\TO\\FILE.CSV"
While this is great, I can't figure out how to make this work with a variable, or better yet with a function. See this comment which I believe is asking the same question.
This one can't even be evaluated:
construct_path <- function(my_path) {
r"my_path"
}
Error: malformed raw string literal at line 2
}
Error: unexpected '}' in "}"
Nor this attempt:
construct_path_2 <- function(my_path) {
paste0(r, my_path)
}
construct_path_2("(C:\THIS\IS\MY\PATH\TO\FILE.CSV)")
Error: '\T' is an unrecognized escape in character string starting ""(C:\T"
Desired output
# pseudo-code
my_path <- "C:\THIS\IS\MY\PATH\TO\FILE.CSV"
construct_path(path)
#> [1] "C:\\THIS\\IS\\MY\\PATH\\TO\\FILE.CSV"
EDIT
In light of #KU99's comment, I want to add the context to the problem. I'm writing an R script to be run from command-line using WIndows's CMD and Rscript. I want to let the user who executes my R script to provide an argument where they want the script's output to be written to. And since Windows's CMD accepts paths in the format of C:\THIS\IS\MY\PATH\TO, then I want to be consistent with that format as the input to my R script. So ultimately I want to take that path input and convert it to a path format that is easy to work with inside R. I thought that the r"()" thing could be a proper solution.
I think you're getting confused about what the string literal syntax does. It just says "don't try to escape any of the following characters". For external inputs like text input or files, none of this matters.
For example, if you run this code
path <- readline("> enter path: ")
You will get this prompt:
> enter path:
and if you type in your (unescaped) path:
> enter path: C:\Windows\Dir
You get no error, and your variable is stored appropriately:
path
#> [1] "C:\\Windows\\Dir"
This is not in any special format that R uses, it is plain text. The backslashes are printed in this way to avoid ambiguity but they are "really" just single backslashes, as you can see by doing
cat(path)
#> C:\Windows\Dir
The string literal syntax is only useful for shortening what you need to type. There would be no point in trying to get it to do anything else, and we need to remember that it is a feature of the R interpreter - it is not a function nor is there any way to get R to use the string literal syntax dynamically in the way you are attempting. Even if you could, it would be a long way for a shortcut.

How to parse #{TEST TAGS} into only the Tags, eliminating current formatting?

Situation.. I have two tags defined, then I try to output them to the console. What comes out seems to be similar to an array, but I'd like to remove the formatting and just have the actual words outputted.
Here's what I currently have:
[Tags] ready ver10
Log To Console \n#{TEST TAGS}
And the result is
['ready', 'ver10']
So, how would I chuck the [', the ', ' and the '], thus only retaining the words ready and ver10?
Note: I was getting [u'ready', u'ver10'] - but once I got some advice to make sure I was running Python3 RobotFramework - after uninstalling robotframework via pip, and now only having robotframework installed via pip3, the u has vanished. That's great!
There are several ways to do it. For example, you could use a loop, or you could convert the list to a string before calling log to console
Using a loop.
Since the data is a list, it's easy to iterate over the list:
FOR ${tag} IN #{Test Tags}
log to console ${tag}
END
Converting to a string
You can use the evaluate keyword to convert the list to a string of values separated by a newline. Note: you have to use two backslashes in the call to evaluate since both robot and python use the backslash as an escape character. So, the first backslash escapes the second so that python will see \n and convert it to a newline.
${tags}= evaluate "\\n".join($test_tags)
log to console \n${tags}

How can I keep toJSON from quoting my JSON string in R?

I am using OpenCPU and R to create a web API that takes in some inputs and returns a topoJSON file from a database, as well as some other information. OpenCPU automatically pushes the output through toJSON, which results in JSON output that has quoted JSON in it (i.e., the topoJSON). This is obviously not ideal--especially since it then gets incredibly cluttered with backticked quotes (\"). I tried using fromJSON to convert it to an R object, which could then be converted back (which is incredibly inefficient), but it returns a slightly different syntax and the result is that it doesn't work.
I feel like there should be some way to convert the string to some other type of object that results in toJSON calling a different handler that tells it to just leave it alone, but I can't figure out how to do that.
> s <- '{"type":"Topology","objects":{"map": "0"}}'
> fromJSON(s)
$type
[1] "Topology"
$objects
$objects$map
[1] "0"
> toJSON(fromJSON(s))
{"type":["Topology"],"objects":{"map":["0"]}}
That's just the beginning of the file (I replaced the actual map with "0"), and as you can see, brackets appeared around "Topology" and "0". Alternately, if I just keep it as a string, I end up with this mess:
> toJSON(s)
["{\"type\":\"Topology\",\"objects\":{\"0000595ab81ec4f34__csv\": \"0\"}}"]
Is there any way to fix this so that I just get the verbatim string but without quotes and backticks?
EDIT: Note that because I'm using OpenCPU, the output needs to come from toJSON (so no other function can be used, unfortunately), and I can't do any post-processing.
To it seems you just want the values rather than vectors. Set auto_unbox=TRUE to turn length-one vectors into scalar values
toJSON(fromJSON(s), auto_unbox = TRUE)
# {"type":"Topology","objects":{"map":"0"}}
That does print without escaping for me (using jsonlite_1.5). Maybe you are using an older version of jsonlite. You can also get around that by using cat() to print the result. You won't see the slashes when you do that.
cat(toJSON(fromJSON(s), auto_unbox = TRUE))
You can manually unbox the relevant entries:
library(jsonlite)
s <- '{"type":"Topology","objects":{"map": "0"}}'
j <- fromJSON(s)
j$type <- unbox(j$type)
j$objects$map <- unbox(j$objects$map)
toJSON(j)
# {"type":"Topology","objects":{"map":"0"}}

Send expression to website return dynamic result (picture)

I use http://www.regexper.com to view a picto representation regular expressions a lot. I would like a way to ideally:
send a regular expression to the site
open the site with that expression displayed
For example let's use the regex: "\\s*foo[A-Z]\\d{2,3}". I'd go tot he site and paste \s*foo[A-Z]\d{2,3} (note the removal of the double slashes). And it returns:
I'd like to do this process from within R. Creating a wrapper function like view_regex("\\s*foo[A-Z]\\d{2,3}") and the page (http://www.regexper.com/#%5Cs*foo%5BA-Z%5D%5Cd%7B2%2C3%7D) with the visual diagram would be opened with the default browser.
I think RCurl may be appropriate but this is new territory for me. I also see the double slash as a problem because http://www.regexper.com expects single slashes and R needs double. I can get R to return a single slash to the console using cat as follows, so this may be how to approach.
x <- "\\s*foo[A-Z]\\d{2,3}"
cat(x)
\s*foo[A-Z]\d{2,3}
Try something like this:
Query <- function(searchPattern, browse = TRUE) {
finalURL <- paste0("http://www.regexper.com/#",
URLencode(searchPattern))
if (isTRUE(browse)) browseURL(finalURL)
else finalURL
}
x <- "\\s*foo[A-Z]\\d{2,3}"
Query(x) ## Will open in the browser
Query(x, FALSE) ## Will return the URL expected
# [1] "http://www.regexper.com/#%5cs*foo[A-Z]%5cd%7b2,3%7d"
The above function simply pastes together the web URL prefix ("http://www.regexper.com/#") and the encoded form of the search pattern you want to query.
After that, there are two options:
Open the result in the browser
Just return the full encoded URL

String continuation across multiple lines, no newline characters

Am using the RODBC library to bring data into R. I have a long query that I want to pass a variable to, much like this SO user.
Problem is that R interprets the whitespace/carriage returns in my query as a newline '\n'.
The accepted solution for this question suggests to simply break up the text into chunks and then paste() together - which works, but ideally I'd like to keep the whitespace intact - makes it easier to test/verify the behavior of the query over in the database before pasting into R.
In other languages I'm familiar with there's a simple line continuation character - indeed, several of the comments on the accepted answer are looking for an approach similar to python's \.
I found an aside to a workaround using strwrap deep in the bowels of an R discussion lists, so in the interest of making the internet better I will post it here. However, if someone can point the direction toward a more elegant/straightforward solution, I will happily accept your answer.
I don't know if you will find this helpful or not, but I have eventually gravitated towards keeping my SQL separate from my R scripts. Keeping the query in my R script, except for very very short ones, I find gets unreadable very quickly.
These days, I tend to keep queries that are more than a single line in their own separate .sql file. Then I can keep them nice and formatted and readable in a nice text editor, and read them into R as needed via something like this:
read_sql <- function(path){
stopifnot(file.exists(path))
sql <- readChar(path,nchar = file.info(path)$size)
sql
}
For binding parameters into the queries, I just keep a %s where the parameter will go in the .sql file, and then add in the parameters in R using sprintf.
I've been much happier this way, as I was finding that cluttering up my R scripts with really long paste statements and multi-line character objects was making my code really hard to read.
R's strwrap will destroy whitespace, including newline characters, per the documentation.
Essentially, you can get the desired behavior by initially letting R introduce line breaks/newline \ns, and then immediately stripping them out.
#make query using PASTE
query_1 <- paste("SELECT map.ps_studentid
,students.first_name || ' ' || students.last_name AS full_name
,map.testritscore
,map.termname
,map.measurementscale
FROM map$comprehensive_with_growth map
JOIN students
ON map.ps_studentid = students.id
WHERE map.termname = '",map_term,"'", sep='')
#remove newline characters introduced above.
#width is an arbitrary big number-
#it just needs to be longer than your string.
query_1 <- strwrap(query_1, width=10000, simplify=TRUE)
#execute the query
map_njask <- sqlQuery(XE, query_1)
query <- gsub(pattern='\\s',replacement="",x=query)
Try using sprintf to get variable substitution, and then replacing all newlines and whitespace.
See my answer to a similar question for details.

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