r - How can I create new column in data frame by aggregating rows? -


i have large (~200k rows) dataframe structured this:

df <-  data.frame(c(1,1,1,1,1), c('blue','blue','blue','blue','blue'), c('m','m','m','m','m'), c(2016,2016,2016,2016,2016),c(3,4,5,6,7), c(10,20,30,40,50))  colnames(df) <- c('id', 'color', 'size', 'year', 'week','revenue')

let's week 7, , want compare trailing 4 week average of revenue current week's revenue. create new column average when of identifiers match. 

df_new <-  data.frame(1, 'blue', 'm', 2016,7,50, 25 )  colnames(df_new) <- c('id', 'color', 'size', 'year', 'week','revenue', 't4ave')

how can accomplish efficiently? thank help

good question. loops pretty inefficient, since have check conditions of prior entries, solution can think of (mind you, i'm intermediate @ r):

for (i in 1:nrow(df)) {     # condition entries match     if ((i > 5) && (df$id[i] == df$id[i-1] == df$id[i-2] == df$id[i-3] == df$id[i-4])     && (df$color[i] == df$color[i-1] == df$color[i-2] == df$color[i-3] == df$color[i-4])     && (df$size[i] == df$size[i-1] == df$size[i-2] == df$size[i-3] == df$size[i-4])     && (df$year[i] == df$year[i-1] == df$year[i-2] == df$year[i-3] == df$year[i-4])     && (df$week[i] == df$week[i-1] == df$week[i-2] == df$week[i-3] == df$week[i-4]))      # avg of last 4 entries' revenues     avg <- mean(df$revenue[i-1] + df$revenue[i-2] + df$revenue[i-3] + df$revenue[i-4])      # create new variable of difference between entry , last 4's     df$diff <- df$revenue[i] - avg }

this code take forever, should work. if 1 time thing when code needs run, should okay. otherwise, others able advise.


Comments

Post a Comment

Popular posts from this blog

Is there a better way to structure post methods in Class Based Views -

i'm using class based views in django , never specify url in ajax calls , omit action parameter in form because know these requests go through post method of class based view. notice view - profile page make many requests depending on user updating on page - post method become convoluted , if/else mess example: def post(self, request, *args, **kwargs): # handle user changing available date if request.post.get('availabledate') != none: self.updateavailabledate(request) return jsonresponse({'result':'success'}) if request.post.get('newprojectname') != none: creative_user = creativeuserprofile.objects.get(id = request.user.id) project = project.create_project(creative_user, request.post['newprojectname']) project.save() return jsonresponse({'projectid': project.id }) if request.post.get('projectimage') != none , request.files['file']: proj...
Read more

performance - Why is XCHG reg, reg a 3 micro-op instruction on modern Intel architectures? -

i'm doing micro-optimization on performance critical part of code , came across sequence of instructions (in at&t syntax): add %rax, %rbx mov %rdx, %rax mov %rbx, %rdx i thought had use case xchg allow me shave instruction , write: add %rbx, %rax xchg %rax, %rdx however, dimay found agner fog's instruction tables , xchg 3 micro-op instruction 2 cycle latency on sandy bridge, ivy bridge, broadwell, haswell , skylake. 3 whole micro-ops , 2 cycles of latency! 3 micro-ops throws off 4-1-1-1 cadence , 2 cycle latency makes worse original in best case since last 2 instructions in original might execute in parallel. now... cpu might breaking instruction micro-ops equivalent to: mov %rax, %tmp mov %rdx, %rax mov %tmp, %rdx where tmp anonymous internal register , suppose last 2 micro-ops run in parallel latency 2 cycles. given register renaming occurs on these micro-architectures, though, doesn't make sense me done way. why wouldn't register renamer ...
Read more

c# - Asp.net web api : redirect unauthorized requst to forbidden page -

im trying redirect unauthorized request forbidden page instead i'm getting forbidden page in response body , how can fix ? here's startup class : app.createperowincontext(storecontext.create); app.createperowincontext<applicationusermanager>(applicationusermanager.create); app.createperowincontext<applicationsigninmanager>(applicationsigninmanager.create); app.usecookieauthentication(new cookieauthenticationoptions { authenticationtype = defaultauthenticationtypes.applicationcookie, expiretimespan = timespan.fromdays(30), }); app.useexternalsignincookie(defaultauthenticationtypes.externalcookie); app.usetwofactorsignincookie(defaultauthenticationtypes.twofactorcookie, timespan.fromminutes(5)); app.usetwofactorrememberbrowsercookie(defaultauthenticationtypes.twofactorrememberbrowsercookie); the method im trying reach : [httpget] [authorize(roles = "admin")] public string getcurrentusername() { return userman...
Read more