r - Pass vector of column names to paste() within mutate (dplyr) -


i'm trying write function takes 1 of arguments vector of column names user. column names used specify columns of dataframe pasted form new column within dplyr::mutate. tried collapse elements of argument vector first , use collapsed string in mutate - wrong. see latest attempt below. made other attempts i'm not understanding new quo, enquo, uq, !!!, !!, , on within dplyr. can show need do?

df <- data.frame(.yr = c("2000", "2001", "2002"), .mo = c("12", "01", "02"), .other = rnorm(3)) cols <- colnames(df)[1:2]  do_want <- df %>%   mutate(new = paste(.yr, .mo, sep = "-"))  my_func <- function(dat, vars){   .vars <- paste(vars, collapse = ",")    result <- dat %>%     mutate(new = paste(.vars, sep = "-" ))   return(result) }  my_func(dat = df, vars = cols)

edit: attempt @ using quo , !! in function definition. result column of repeated string ".yr,.mo" 

my_func <- function(dat, vars){   .vars <- quo(paste(vars, collapse = ","))    result <- dat %>%     mutate(new = paste(!!.vars, sep = "-" ))   return(result) }

because have list of strings, can use rlang::syms in function take strings , turn them symbols. can use !!! splice arguments put paste.

my_func <- function(dat, vars){      .vars <- rlang::syms(vars)       result <- dat %>%           mutate(new = paste(!!!.vars, sep = "-" ))      return(result) }  my_func(dat = df, vars = cols)     .yr .mo     .other     new 1 2000  12 -0.2663456 2000-12 2 2001  01  0.5463433 2001-01 3 2002  02 -1.3133078 2002-02

Comments

Post a Comment

Popular posts from this blog

android - InAppBilling registering BroadcastReceiver in AndroidManifest -

i'm implementing inapp billing in android app. works well, however, i'm trying decouple broadcast receiver activity manifest. suggestion in android's trivialdrive sample: // important: dynamically register broadcast messages updated purchases. // register receiver here instead of <receiver> in manifest // because call getpurchases() @ startup, therefore can ignore // broadcasts sent while app isn't running. // note: registering listener in activity bad idea, done here // because sample. regardless, receiver must registered after // iabhelper setup, before first call getpurchases(). currently there's class extends broadcastreceiver : public class iabbroadcastreceiver extends broadcastreceiver { /** * intent action receiver should filter for. */ public static final string action = "com.android.vending.billing.purchases_updated"; private final iabbroadcastlistener mlistener; public iabbroadcastreceiver(iabbroadcastlistener listener) { m...
Read more

python Tkinter Capturing keyboard events save as one single string -

is possible store keyboard events 1 string? code below stores 1 char , prints it. card reader or bar code reader, contains collection of character/ string not 1 character @ time. goal save char pressed text variable. from tkinter import * root = tk() def key(event): text= event.char text+= event.char print ("pressed", text) def callback(event): frame.focus_set() print ("clicked at", event.x, event.y) frame = frame(root, width=100, height=100) frame.bind("<key>", key) frame.bind("<button-1>", callback) frame.pack() root.mainloop() currently, creating text variable , everytime key() function gets called, , text stores last character typed. you can define text module level variable , , use module level text inside key function - text = '' def key(event): global text text+= event.char print("pressed", text)
Read more

sql server - Why does Linq-to-SQL add unnecessary COUNT()? -

here tables: create table customer ( cid int primary key, name varchar(32) ) create table ord ( oid int primary key, cid int foreign key references customer, address varchar(20) ) here's linq-to-sql statement: var aaa = c in db.customer select new { c, o = c.ord.tolist() }; and here's inexplicable query generated linq-to-sql: select [t0].[cid] [cid], [t0].[name] [name], [t1].[oid] [oid], [t1].[cid] [cid2], [t1].[address] [address], (select count(*) [dbo].[ord] [t2] [t2].[cid] = [t0].[cid]) [value] [dbo].[customer] [t0] left outer join [dbo].[ord] [t1] on [t1].[cid] = [t0].[cid] order [t0].[cid], [t1].[oid] i want understand how rid of count(*) part. it's entirely uncalled for! linq needs count(*) in order determine number of entries returned o = c.ord.tolist() .
Read more