Ruby: Hash, Arrays and Objects for storage information -


i learning ruby, reading few books, tutorials, foruns , one... so, brand new this. trying develop stock system can learn doing. questions following:

i created following store transactions: (just few parts of code)

transactions.push type: "buy", date: date.strptime(date.to_s, '%d/%m/%y'), quantity: quantity, price: price.to_money(:brl), fees: fees.to_money(:brl)

and 1 colleague here suggested create transaction class store this. so, next storage information had, did:

@dividends_from_stock << dividendsfromstock.new(row["approved"], row["value"], row["type"], row["last day with"], row["payment day"])

now, first question: way better? hash in array or object in array? , why?

this @dividends_from_stock returned method 'dividends'.

i want find dividends paid above specific date:

puts ciel3.dividends.find_all {|dividend| date.parse(dividend.last_day_with) >  date.parse('12/05/2014')}

i following:

#<dividendsfromstock:0x2785e60> #<dividendsfromstock:0x2785410> #<dividendsfromstock:0x2784a68> #<dividendsfromstock:0x27840c0> #<dividendsfromstock:0x1ec91f8> #<dividendsfromstock:0x2797ce0> #<dividendsfromstock:0x2797338> #<dividendsfromstock:0x2796990>

ok able spot (i think) objects has date higher 12/05/2014. (second question) how can information regarding 'value' (or other information) stored inside objects?

  1. generally better define classes. classes have names. understand going on when program gets big. can see class of each variable this: var.class. if use hashes everywhere, confused because these calls return hash. if define classes things, see class names.
  2. define methods in classes return information need. if define method called to_s, ruby call behind scenes on object when print or use in interpolation (puts "some #{var} here").

Comments

Post a Comment

Popular posts from this blog

jOOQ update returning clause with Oracle -

according http://www.jooq.org/doc/3.8/manual/sql-building/sql-statements/update-statement/ jooq doesn't support returning clause in update statements databases except firebird , postgres. does know, still correct oracle jooq? according oracle's documentation, oracle db supports returning clase delete, insert, or update statements. incorrect manual you're right - manual wrong , should fixed: https://github.com/jooq/jooq/issues/5470 single row update returning jooq 3.8 added support single row update .. returning statements. internally, uses callablestatement , pl/sql block of form: begin update "my_table" set "my_table"."column" = 'xyz' "my_table"."id" = 1 returning "my_table"."id", "my_table"."column" ?, ?; ? := sql%rowcount; end; the relevant issue is: https://github.com/jooq/jooq/issues/5190 multi row update returning a...
Read more

java - Warning equals/hashCode on @Data annotation lombok with inheritance -

i have entity inherits other. on other hand, i'm using lombok project reduce boilerplate code, put @data annotation. annotation @data inheritance produces next warning: generating equals/hashcode implementation without call superclass, though class not extend java.lang.object. if intentional, add '@equalsandhashcode(callsuper=false)' type. is advisable add annotation @equalsandhashcode (callsuper = true) or @equalsandhashcode (callsuper = false) ? if not added, 1 callsuper=false or callsuper=true ? the default value false . 1 if don't specify , ignore warning. yes, recommended add @equalsandhashcode annotation on @data annotated classes extend else object. cannot tell if need true or false , depends on class hierarchy, , need examined on case-by-case basis. however, project or package, can configure in lombok.config call super methods if not direct subclass of object. lombok.equalsandhashcode.callsuper = call for configuration system ...
Read more

java - BasicPathUsageException: Cannot join to attribute of basic type -

i using java 8 jpa (hibernate 5.2.1). have clause works perfectly, until introduce clause make use foreign key table values too. i getting following error: basicpathusageexception: cannot join attribute of basic type i think problem related fact have join table, , not sure how create join using join table. employee - employee_category - category model (employee.java): @manytomany(cascade = cascadetype.all, fetch=fetchtype.eager) @jointable ( name="employee_category", joincolumns={ @joincolumn(name="emp_id", referencedcolumnname="id") }, inversejoincolumns={ @joincolumn(name="cat_id", referencedcolumnname="id") } ) private set<category> categories; model (category.java): @id private string id; jpa when introduce following code, fails error above (i think problem new piece of code): join<t, category> category = from.join("id"); predicates.add(criteriabuilder.like(category....
Read more