r - Update a subset of a df with mutate_each -

-

i have dplyr dataframe 100k+ rows , ~200 columns. there 15 columns contain date values in excel format (# of days since jan 1, 1900), column names contain date string makes easy subset dataframe.

library(dplyr)  x <- data.frame(date1 = 45000+ 500*rnorm(100),            date2 = 50000+ 500*rnorm(100),            var1 = 50 * rnorm(100),            var2 = 100 + 20 * rnorm(100))  > x %>% head      date1    date2       var1      var2 1 44952.83 49432.88   8.125523 125.95802 2 44331.47 49231.76 -34.814162 117.26881 3 44597.69 49651.91  27.747881 108.45787 4 45113.50 49802.87  24.584569  83.84904 5 46212.14 49972.59  72.444414  80.61595 6 45753.38 50074.57 -34.927552 127.70018  date_cols <- x %>% select(contains('date', ignore.case=t)) %>% names > date_cols [1] "date1" "date2"

i'd change these date columns actual r datetimes without changing other columns. can't figure out how update date_cols subset of dataframe:

x %>% select_(.dots = date_cols) %>%        mutate_each(funs(as.date(., origin="1900-01-01"))) %>%        head         date1      date2 1 2023-01-28 2035-05-05 2 2021-05-17 2034-10-16 3 2022-02-07 2035-12-10 4 2023-07-08 2036-05-09 5 2026-07-11 2036-10-26 6 2025-04-08 2037-02-05

i've tried following doesn't work:

x %>% select_(.dots = date_cols) <- x %>% select_(.dots = date_cols) %>%    mutate_each(funs(as.date(., origin="1900-01-01")))

i guess there better way "rbinding" original dataframe without date columns date_colssubset once mutated.

as commented @alistaire, can use mutate_at convert date columns , keep rest of data frames unchanged, can avoid binding original data frame subsets:

library(dplyr) mux <- x %>% mutate_at(vars(contains('date')), funs(as.date(., origin="1900-01-01")))  head(mux) #        date1      date2       var1      var2 # 1 2021-11-09 2038-10-20  44.524710  86.15957 # 2 2020-06-04 2037-08-04  31.402905  94.74633 # 3 2023-12-22 2038-03-06  31.600929  85.90605 # 4 2020-05-08 2037-01-02   7.140777  82.80565 # 5 2025-03-25 2038-07-30 -54.913577 100.83949 # 6 2021-02-18 2034-06-20  28.616670  93.92246

and according ?mutate_at:

summarise_each() , mutate_each() older variants deprecated in future.

better used these new apis.


Comments

Post a Comment

Popular posts from this blog

sequelize.js - Sequelize group by with association includes id -

-
so when requesting group sequelize follows: return models.workingcalendar .findall({ attributes: [ 'workingcalendar.periodid', 'workingcalendar.date', 'period.name' ], include: [ { model: models.period, attributes: [] } ], where: { getsudoid: currentgetsudo.id, unitplantid: unitplantid }, group: ['workingcalendar.periodid', 'workingcalendar.date', 'period.name'], }); sequelize run query: select [workingcalendar].[id], [workingcalendar].[periodid], [workingcalendar].[date], [period].[name] [workingcalendars] [workingcalendar] left outer join [periods] [period] on [wor...
Read more

c++ - Migration from QScriptEngine to QJSEngine -

-
i'm migrating qscriptengine code on qjsengine. now, have: class pars { public: static qscriptvalue printmainlog(qscriptcontext* c, qscriptengine* e); }; qscriptvalue pars::printmainlog(qscriptcontext* c, qscriptengine* e) { //some actions return e->globalobject().property(""); } ... qscriptengine engine; ... engine.globalobject().setproperty("printlog",engine.newfunction(pars::printmainlog)); so, user can put printlog("what ever"); in application in , example, qlineedit , function pars::printmainlog evalute. is there way qjsengine? so, user put same printlog("what ever");? way find here , user should put logger.printlog("what ever"); logger class inherited qobject printlog slot.
Read more

delphi - Take screenshot in webcam using VFrames in Console Application -

-
i'm doing program take picture of webcam using delphi xe2 , vframes achieve this, problem have figured out, in graphic application works fine, when use unit in console application, returns me error saying first chance exception @ $76b6b727. exception class eaccessviolation message 'access violation @ address 004a271b in module 'console.exe'. read of address 00000260'. process console.exe (3676) my unit : unit webcam; interface uses sysutils, windows, vcl.imaging.jpeg, vcl.graphics, vsample, vframes, classes; type twebcam = class private procedure newvideoframeevent(sender: tobject; width, height: integer; dataptr: pointer); public constructor create; destructor destroy; override; procedure capture_webcam(take_name: string); end; var web_image: tvideoimage; name_screen: string; implementation constructor twebcam.create; begin inherited create; end; destructor twebcam.destroy; begin inherited destroy; end; ...
Read more