Hypertechblog

go to your terminal create a directory mkdir ruby_data_scrapping create directory mkdir lib cd lib/ touch scraper.rb gem install nokogiri  // install gems in local gem install httparty gem install byebug Write code in your scraper.rb require "httparty" require "nokogiri" require "byebug" class Scraper   attr_accessor :parse_page   def initialize       doc = HTTParty.get("https://in.tradingview.com/markets/currencies/rates-africa/")       @parse_page ||= Nokogiri::HTML(doc)   end   def get_prices      item_container.first(2).last.children.map{|x| x.text}   end   private     def item_container        parse_page.css(".tv-data-table__tbody").first.css(".tv-screener-table__result-row").css(".tv-screener-table__cell")     end   prices = Scraper.new.get_prices   (0...prices.size).each do |index|       puts "Price: #{prices[index]}"   end end now run this scraper ruby scraper.rb

Show Escape or Enter and tab in column or row in Rails @users.each do |user|      raw(user.address.gsub(/\n/, '<br>'))   end //assuming you have \n or enter in your record and if you have another Special character then replace that character wiht respective html tag

DATATYPES IN SQL  The data type represents the type of data to be entered into a column and Db engine can assign memory for thevalue entered into the column. There are 5 types of DataType in sql. String DataTypes Numeric DataTypes Date Datatypes Binary DataTypes LOB--Large Objects String Data Types These data types support sequence of character, digits and any symbol from keyboard. CHAR(size) It is used to store fixed length character strings. By default the size is 1 character, and max size is 2000 chars orbytes. Ex: student_id, email, address and so on VARCHAR2(size) It is used to store variable length character strings. No default size. we should specify size and max size is 4000 chars /bytes. Ex: emp names, addresses, descriptions, city names. LONG It is used to store variable length char data(similar to varchar2 data type) but max size is 2 GB NOTE: Only one long type column is allowed per a table. 1) NUMBER(Precision, [Scale])    It is used to store numb

Types of SQL commands 1) DDL(data definition language) commands:       Used to create or change or delete any data base objects CREATE ALTER DROP TRUNCATE RENAME 2) DML(data manipulation language) COMMANDS       Used to fetch data / enter new data/ changing existed data / deleting the data from table. INSERT  UPDATE  DELETE  TRUNCATE 3) DRL(dataretrieval language) Command     SELECT (logicalcommand) 4) DCL(DATA CONTROL LANGUAGE) COMMANDS     Used to control the access of data base objects. These commands are used by DBA (databaseadministrator) GRANT  REVOKE 5) TCL(TRANSACTION CONTROL LANGUAGE) COMMANDS      Used to save or cancel the actions/transactions made on table data. COMMIT  ROLLBACK  SAVEPOINT

In java or other object oriented programming language is-a and has-a are two type of relationship under the concepts of inheritance. suppose we have three class Car. subaru. engine. subaru is a car — its a is-a  relationship  between  class  subaru and  class  car. car has a engine — its a has-a  relationship  between  class  car and  class  engine.

The exp() function computes the exponential (Euler's number) raised to the given argument. C exp() Prototype double exp(double arg); The exp(arg) takes a single argument and returns the value in type   double . — maths e^x = exp(x) [in c programming] It is defined in  <math.h> header file. EXAMPLE- #include <stdio.h> #include <math.h> int main () { double x = 12.0 , result ; result = exp ( x ); printf ( "Exponential of %.2lf = %.2lf" , x , result ); return 0 ; } Output Enter the value of x to find e ^ x : 12 Exponential of 12.00 = 162754.79

A   structure   enables us to treat a number of different variable stored at different places in memory. A  union   enables us to treat the same space in memory as a number of different variable.

Bit fields are not portable . Because  bit fields cannot span machine words , and because the number of bits in a machine word is different on different machines, a particular program using bit fields might not even compile on a particular machine. Assuming that your program does compile, the order in which bits are assigned to bit fields is not defined. Therefore, different compilers, or even different versions of the same compiler, could produce code that would not work properly on data generated by compiled older code. Stay away from using bit fields, except in cases in which the machine can directly address bits in memory and the compiler can generate code to take advantage of it and the increase in speed to be gained would be essential to the operation of the program.