r - How to calculate the total value based on multiple column values -


i have data frame contains client names , area data.

i want calculate total area each client areas span on multiple floors (for example, client a may have 202 on floor 1 , 248 on floor 2).

i want create new column total area.

i know how create new column:

areas$new_area

and know how calculate total area each client (manually):

sum(areas[areas$client == "client a", "areas"])

what having difficulty iterating through data frame , automating entire process.

i came partial solution iterates through data frame, calculates sum of each area value every client @ position i (which know happen because takes single value in area column, of course):

for(i in 1:nrow(areas)){   areas$new_area[i] <- sum(areas$areas[i]) }

also, suspect/know apply function approach take here, don't know 1 use nor how apply (no pun intended).

how can a) achieve , b) achieve in cleaner way?

my expected output (or variation of it):

-------------------------------------- | client | floor | area |  new area  | -------------------------------------- |      |   1   | 202  |    202     | -------------------------------------- |      |   2   | 248  |    450     | -------------------------------------- |   b    |   1   | 1000 |    1000    | -------------------------------------- |   b    |   2   | 150  |    1150    | --------------------------------------

i want new column @ end total of area values each client (my example shows cumulative total, whether cumulative or not doesn't matter - merely purpose of giving example).

summedareas <- aggregate(area ~ client, areas, sum) allyourdata <- merge(area, summedareas, = "client")

i prefer aggregate on tapply because nice data.frame back, calculate totals 

tapply(x = areas$area, index = areas$client, fun = sum)

Comments

Post a Comment

Popular posts from this blog

Sort a complex associative array in PHP -

this question has answer here: php sort array subarray value 5 answers i have associative array in php like: $newarray1 = array ( [producta] => array ( [link] => http://sanjosespartan.com/blog/products/agile-java-development/ [visitcount] => 4 ) [productd] => array ( [link] => http://sanjosespartan.com/blog/products/intro-to-go/ [visitcount] => 1 ) [productg] => array ( [link] => http://sanjosespartan.com/blog/products/node-js-for-developers/ [visitcount] => 1 ) [productb] => array ( [link] => http://sanjosespartan.com/blog/products/beginning-mysql/ [visitcount] => 1 ) [productc] => array ( [link] => http://sanjosespartan.com/blog/products/computer-networks/ [visitcount] => 1 ) ...
Read more

vb.net - How to ignore if a cell is empty nothing -

how use roscolor() ignore value (like empty cell) ? color row if value upper 5 when there nothing in cell, want ignore roscolor() apply, how? public sub roscolor() integer = 0 quotedatagridview1.rows.count() - 1 step +1 dim val integer val = quotedatagridview1.rows(i).cells(3).value if val = vbempty quotedatagridview1.rows(i).defaultcellstyle.backcolor = color.white elseif val < 5 quotedatagridview1.rows(i).defaultcellstyle.backcolor = color.red elseif val > 5 , val < 10 quotedatagridview1.rows(i).defaultcellstyle.backcolor = color.lightyellow end if next end sub you can check empty value following public sub roscolor() integer = 0 quotedatagridview1.rows.count() - 1 step +1 dim val = quotedatagridview1.rows(i).cells(3).value if isdbnull(val) or val nothing quotedatagridview1.rows(i).defaultcellstyle.backcolor = color.white ...
Read more

recursion - Can every recursive algorithm be improved with dynamic programming? -

i first year undergraduate csc student looking competitive programming. recursion involves defining , solving sub problems. understand, top down dynamic programming (dp) involves memoizing solutions sub problems reduce time complexity of algorithm. can top down dp used improve efficiency of every recursive algorithm overlapping sub problems? dp fail work , how can identify this? the short answer is: yes. however, there constraints. obvious 1 recursive calls must overlap. i.e. during execution of algorithm, recursive function must called multiple times same parameters. lets truncate recursion tree memoization. can use memoization reduce number of calls. however, reduction of calls comes price. need store results somewhere. next obvious constraint need have enough memory. comes not-so obvious constraint. memory access requires time. first need find result stored , maybe copy location. in cases, might faster let recursion calculate result instead of loading somewher...
Read more