Pyspark Array Key,Value -

-

i have rdd array stores key-value pair key 2d indices of array , value number @ spot. example [((0,0),1),((0,1),2),((1,0),3),((1,1),4)] want add values of each key surrounding values. in relation earlier example, want add 1,2,3 , place in (0,0) key value spot. how this?

i suggest following:

  1. define function that, given pair (i,j), returns list pairs corresponding positions surrounding (i,j), plus input pair (i,j). instance, lets function called surrounding_pairs(pair). then:

    surrounding_pairs((0,0)) = [ (0,0), (0,1), (1,0) ] surrounding_pairs((2,3)) = [ (2,3), (2,2), (2,4), (1,3), (3,3) ]

    of course, need careful , return valid positions.

  2. use flatmap on rdd follows:

    myrdd = myrdd.flatmap(lambda (pos, v): [(p, v) p in surrounding_pairs(pos)])

    this map rdd [((0,0),1),((0,1),2),((1,0),3),((1,1),4)] 

    [((0,0),1),((0,1),1),((1,0),1),  ((0,1),2),((0,0),2),((1,1),2),  ((1,0),3),((0,0),3),((1,1),3),  ((1,1),4),((1,0),4),((0,1),4)]

    this way, value @ each position "copied" neighbour positions.

  3. finally, use reducebykey add corresponding values @ each position: 

    from operator import add myrdd = myrdd.reducebykey(add)

i hope makes sense.


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