r - Nested list to data frame and back to nested list -


consider nested list data rectangular.

mylst1 <- list(   "system" = list(     "subjectid" = c(101,102,103),     "procedureid" = c(202,202,203)   ),   "demographics" = list(     "demo_age" = c(12,22,32),     "demo_gender" = c(1,0,1)   ),   "items" = list(     "n" = list(       "n001" = c(1,2,3),       "n002" = c(3,2,1)       ),     "e" = list(       "e001" = c(1,2,3),       "e002" = c(3,2,1)     )   ) )

since nested lists awkward work with, let's create data frame: mydf <- data.frame(mylst1)

so far good, can perform operations on mydf. let's assume filtered observations. problem need return same nested list structure required web application want send data to, data of course looks this:

> str(mydf)     'data.frame':   3 obs. of  8 variables:      $ system.subjectid        : num  101 102 103      $ system.procedureid      : num  202 202 203      $ demographics.demo_age   : num  12 22 32      $ demographics.demo_gender: num  1 0 1      $ items.n.n001            : num  1 2 3      $ items.n.n002            : num  3 2 1      $ items.e.e001            : num  1 2 3      $ items.e.e002            : num  3 2 1

what best solution data in original list format? thinking of using . delimiter each level, i'm unsure how in practice.

thanks

one option relist (assuming columns of same class) in 'mydf'

newlst <- relist(unlist(mydf), skeleton = mylst1) identical(mylst1, newlst) #[1] true

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