r - Predictive power of date variable reduces when changed from as.Date to as.numeric -

-

i'm building regression model several date , numeric variables. quick check on 1 of date variables

    lm.fit = lm(label ~ firstday, data = rawdata)     summary(lm.fit)$r.squared

to gauge predictive influence on model. accounted 41% of variance. attempted change date numeric can work better variable. used command

    as.numeric(as.posixct(rawdata$firstday, format = "%y-%m-%d"))

doing reduced variance 10% - not want. doing wrong , how go it?

i've looked @ https://stats.stackexchange.com/questions/65900/does-it-make-sense-to-use-a-date-variable-in-a-regression answer not clear me.

edit 1:

a reproducible code sample of did shown below:

 label = c(0,1,0,0,0,1,1)  firstday = c("2016-04-06", "2016-04-05", "2016-04-04",      "2016-04-03", "2016-04-02", "2016-04-02","2016-04-01")  lm.fit <- lm(label ~ firstday)  summary(lm.fit)$r.squared  [1] 0.7083333

on changing numeric:

 firstday = as.numeric(as.posixct(firstday, format="%y-%m-%d"))

i get

 lm.fit <- lm(label ~ firstday)  summary(lm.fit)$r.squared   [1] 0.1035539

it's because original list of dates list of items, without date sequence information.

see below how change them arbitrary letters same result. third code snippet returns same r2 first code snippet.

label <- c(0,1,0,0,0,1,1) firstday1<- c("2016-04-06","2016-04-05","2016-04-04","2016-04-03","2016-04-02","2016-04-02","2016-04-01") str(firstday1) lm.fit1 <- lm(label~firstday1) summary(lm.fit1)$r.squared [1] 0.7083333   firstday2 <- as.numeric(as.posixct(firstday1,format="%y-%m-%d")) str(firstday2) lm.fit2 <- lm(label ~ firstday2) summary(lm.fit2)$r.squared [1] 0.1035539   firstday3<- c("a","b","c","d","e","e","f") str(firstday3) lm.fit3 <- lm(label~firstday3) summary(lm.fit3)$r.squared [1] 0.7083333

Comments

Post a Comment

Popular posts from this blog

java - Suppress Jboss version details from HTTP error response -

-
my jboss verson jboss eap 6.3 when kind of error response sent jboss, adds server information response. following sample row response: http/1.1 400 bad request server: apache-coyote/1.1 content-type: text/html;charset=utf-8 content-length: 2391 date: tue, 19 jul 2016 09:30:46 gmt connection: close jboss web/7.4.8.final-redhat-4 - jbweb000064: error report jbweb000065: http status 400 - org.codehaus.jackson.map.jsonmappingexception: can not construct instance of mybean.type string value 'xyz': value not 1 of declared enum instance names @ [source: org.jboss.resteasy.core.interception.messagebodyreadercontextimpl$inputstreamwrapper@5e421c2b; line: 14, column: 26] (through reference chain: requestargs["request"]) jbweb000309: type jbweb000067: status report jbweb000068: message org.codehaus.jackson.map.jsonmappingexception: can not construct instance of mybean.type string value 'xyz': value not 1 of declared enum instance names @ [source: org.jboss...
Read more

gridview - Yii2 DataPorivider $totalSum for a column -

-
i have order , ordersearch models. in order list (actionindex) gridview there filtering , sorting. on of columns in order order_total (sum of products in order). i need implement sum of order_total in gridview. if manually counting activedataprovider->getmodels() array_map spend 3 seconds 3000 orders (localhost). don't want miss time. i see 2 ways make faster: create cache every filter , update lifetime (horrible) the interesting can right in ordersearch->search() method $query method. don't understand how can pass in controller. example of code 2nd way: class ordersearch extends order { public $totalsum; public function search($params) { $query = order::find(); $dataprovider = new activedataprovider([ 'query' => $query, ]); $this->load($params); $this->totalsum = $query->sum('order_total'); // works fast return $dataprovider; } } after i...
Read more

Sass watch command compiles .scss files before full sftp upload -

-
i use winscp download , edit .scss files , sass on linux (on server) compile them .css . after saving file, use: sass scss/style.scss css/style.css , replaces css file compiled sccs. the problem i want skip part return command line after editing scss file, sake of automation , saving time. but, if use watch command: sass --watch scss/style.scss:css/style.css synchronize 2 files, alerts nonexistent css errors pop up: change detected to: scss/style.scss error scss/style.scss (line 232: invalid css after "...ht: bold; line-": expected "{", "") note that when file uploads quicker usual (sometimes happens) watch command job, no errors. this because, when file upload takes time, sass compiles scss file (on server) before uploaded remote folder. thus, compiles part of file, resulting in css errors. is there way set timer watch command waits few seconds after detects changes , before compiling? any other way overcome is, of course, ...
Read more