r - Paste the elements of two columns -

-

this question has answer here:

i have data.frame of following kind

set.seed(12) d = data.frame(a=sample(5,x=1:9),                 b=sample(5,x=1:9),                c=sample(5,x=1:9),                d=sample(5,x=1:9),                e=sample(5,x=1:9),                f=sample(5,x=1:9))  d #   b c d e f # 1 1 1 4 4 2 3 # 2 7 2 7 9 7 5 # 3 8 5 3 8 1 2 # 4 2 9 8 7 5 9 # 5 9 6 2 1 9 4

i take first 2 columns, convert integer characters , paste 2 elements of same row together. repeat process each successive pair of columns.

here script job correctly:

bar = function (twocols) {sapply(1:nrow(twocols), fun=function(x) {paste(twocols[x,], collapse="")} )}      count = 0     out = matrix(0, ncol=ncol(d)/2, nrow=nrow(d))     (i in seq(1,ncol(d), 2)) {        count = count+1        out[,count] = bar(d[,i:(i+1)])     }  print(out)      [,1] [,2] [,3] [1,] "11" "44" "23" [2,] "72" "79" "75" [3,] "85" "38" "12" [4,] "29" "87" "59" [5,] "96" "21" "94"

but data.frame big , looping through whole data.frame in r slow. have more efficient solution? rcpp might solution don't know how code in c++.

this matches description, not output show:

mat = as.matrix(d)  matrix(paste0(mat[, seq(1, ncol(mat), = 2)],               mat[, seq(2, ncol(mat), = 2)]),        ncol = ncol(mat) / 2)  #      [,1] [,2] [,3] # [1,] "11" "44" "23" # [2,] "72" "79" "75" # [3,] "85" "38" "12" # [4,] "29" "87" "59" # [5,] "96" "21" "94"

you could, of course, convert result numeric, data.frame, etc.


Comments

Post a Comment

Popular posts from this blog

PHP DOM loadHTML() method unusual warning -

-
i had following code works fine on localhost: $document = new domdocument(); $document->loadhtml($p_result); $form = $document->getelementsbytagname('form')->item(0); // code continues using $form variable after same code updated on outside server, loadhtml() failed , issued warning. warning: domdocument::loadhtml() expects parameter 1 valid path, string given in path/name/to/script.php returned null instead of object code pretty gets fatal error. note contents of $p_result absolutely same on outside server , on localhost. but why displays kind of warning , why not work? doesn't loadhtml() expects argument 1 string in first place? why method expects parameter 1 valid path ? just make clear i'm not calling loadhtmlfile() , i'm calling loadhtml() . thanks. you're affected one of php bugs . issue present in php 5.6.8 , 5.6.9. have affected php version on server, , bug-free version on localhost. the bug forbids null
Read more

python - How to create jsonb index using GIN on SQLAlchemy? -

-
here's current code creating index jsonb. index("mytable_data_idx_id_key", mytable.data['id'].astext, postgresql_using='gin') but got error. sqlalchemy.exc.programmingerror: (psycopg2.programmingerror) data type text has no default operator class access method "gin" hint: must specify operator class index or define default operator class data type. [sql: "create index event_data_idx_id_key on event using gin ((data ->> 'id'))"] is there way create index on sqlalchemy? the postgresql specific sqlalchemy docs @ http://docs.sqlalchemy.org/en/latest/dialects/postgresql.html#operator-classes mention postgresql_ops dictionary provide "operator class" used postgresql, , provide example illustrating use: index('my_index', my_table.c.id, my_table.c.data, postgresql_ops={ 'data': 'text_pattern_ops',
Read more

c# - TransactionScope not rolling back although no complete() is called -

-
i'm using transactionscope rollback transaction fail bool errorreported = false; action<importerrorlog> newerrorcallback = e => { errorreported = true; errorcallback(e); }; using (var transaction = new transactionscope()) { foreach (importtaskdefinition task in taskdefinition) { loader.load(streamfile, newerrorcallback, task.destinationtable, processingtaskid); } if (!errorreported) transaction.complete(); } i'm sure there no transactionscope started ahead or after code. i'm using entity framework insert in db. regardless state of errorreported transaction never rolled in case of error. what missing ? transactionscope sets transaction.current . that's does. wants transacted must @ property. i believe ef each time connection opened reason. probably, connection open when scope installed. open connection inside of scope or enlist manually. ef has nasty "design decision": default opens
Read more