Function naming for R packages -

-



i writing r package , avoid using function names found in other packages. example, planned call function 'annotate', has been used in nlp package. evidently best avoid obvious name choices, there systematic way search exhaustive list of cran published function names avoid duplication? appreciate important cran shared packages can relevant when sharing locally in case there conflict loaded package.

name clashes occur when 2 packages loaded contain functions same name. so, name clashes can avoided @ 2 places:

  • when defining function names in package
  • when calling functions package

creating functions unique names

at time of writing (23 aug 2017), incredible number of 11272 packages available on cran (the latest figure can found here) , new packages being added every day.

so, creating function names unique today may cause name clashes in future when other packages added.

alistaire has mentioned option prefix functions. besides stringi , stringr, forcats packages example uses prefixes fct_ , lvls_.

this approach may reduce probability of name clashes.

(although it's not guaranteed no other package maintainer might choose same prefix.)

calling functions unambiguously using double colon operator

imho, ultimate responsibility avoiding name clashes user's.

i've seen questions here on more half dozen of packages being loaded. or, library(tidyverse) called convenience, loading 19 other packages dplyrand tidyr have been sufficient.

cluttering namespace many loaded packages increases risk of name clashes. , 2 packages loaded, name clashes might occur. instance, lubridate , data.table package both have defined 

hour, isoweek, mday, minute, month, quarter, second, wday, week, yday, year

which function being called depend on order packages have been loaded. (you may use conflicts() find objects exist same name in 2 or more places on search path.)

to avoid ambiguities , unexpected results, suggest load few packages possible , use double colon operator ?"::" call functions packages without loading package beforehand, e.g.,

library(data.table) dt <- data.table(t = lubridate::now() + 0:3) # call function loaded package data.table dt[, second(t)]  
[1] 18 19 20 21 
# call function lubridate package dt[, lubridate::second(t)] 
[1] 18.88337 19.88337 20.88337 21.88337

there benefit using double colon operator. serve documentation within code package function being called.

this comes @ expense of few additional key strokes may save lot of time when code inspected, amended, or debugged weeks or years later. i've seen many questions on op hasn't mentioned package.





wiki

Comments

Post a Comment

Popular posts from this blog

Asterisk AGI Python Script to Dialplan does not work -

-
i'm stuck project have check database of sip extension incoming caller id , dial sip extension. below receive when run script on asterisk cli. -- registered sip '9125' @ 192.168.1.102:50142 > saved useragent "zoiper rv2.8.40" peer 9125 [2017-08-22 13:53:33] notice[5095]: chan_sip.c:24558 handle_response_peerpoke: peer '9125' reachable. (17ms / 2000ms) == using sip rtp tos bits 184 == using sip rtp cos mark 5 -- executing [0112617769@from-trunk:1] answer("sip/obitrunk1-0000000d", "") in new stack > 0x1ca50d0 -- probation passed - setting rtp source address 192.168.1.98:16834 -- executing [0112617769@from-trunk:2] agi("sip/obitrunk1-0000000d", "test.py") in new stack -- launched agi script /var/lib/asterisk/agi-bin/test.py args: ['/var/lib/asterisk/agi-bin/test.py'] env line: agi_request: test.py env line: agi_channel: sip/obitrunk1-0000000d env line: agi_language: en env line: a
Read more

python - Read npy file directly from S3 StreamingBody -

-
i have many .npy (numpy) , .json files saved in s3, need download , load these files. for json files downloading files , loading dictionary using following code: obj = s3.object(bucket, key) response = obj.get() body = response['body'].read().decode('utf-8') data = json.loads(body) that way avoid writing .json file disk , reading it. now want same .npy files, equivalent? currently downloading file, saving temp file on disk , loading np.load avoid if possible. following https://stackoverflow.com/a/28196540/3509999 : obj = s3.object(bucket, key) io.bytesio(obj.get()["body"].read()) f: # rewind file f.seek(0) arr = np.load(f) wiki
Read more

kotlin - Out-projected type in generic interface prohibits the use of metod with generic parameter -

-
i start using kotlin , defined interface this: interface aadapter<vh : recyclerview.viewholder> { fun oncreateaviewholder(parent: viewgroup): vh fun onbindaviewholder(v: vh, position: int) } and when try use on code: class klasa ( private val adapter: aadapter<*> ) { fun dosth(){ //... val vh = this.adapter.oncreateaviewholder(parent) //on below line error adapter.onbindaviewholder(v, position) //... } } i error out-projected type 'aadapter<*>' prohibits use of 'public abstract fun onbindaviewholder(v: t, position: int): unit i tied add "in" or "out" definition i'm confused. how allow it. replace aadapter<*> aadapter<recyclerview.viewholder> . class klasa ( private val adapter: aadapter<recyclerview.viewholder> ) { // ... because have declared aadapter has type parameter vh type subclass of recyclerview.
Read more