Reading 05 Summary

Comparison operators:

• Evaluating conditions:
  • You can evaluate a situation by comparing one value in the script to what you expect it might be .

  • The result will be a Boolean :

    1. True 
    2.  False 
    

• ( == ) is equal to , it’s compare two values to see if they the same.

• ( != ) is not equal to, it’s compare two values to see if they not the same .

• (===) strict equal to , it’s compare two values to check that both the datatype and the value are the same .

• (!==) strict not equal to, it’s compare two values to check that both the datatype and the value are not the same .

• (>) greater than ,it checks if the number on the left is greater than the number on the right.

• (<) less than , it checks if the number on the left is less than the number on the right .

• ( >=) greater than or equal to, it checks if the number on the left is greater than or equal to the number on the right.

• (<=) less than or equal to, it checks if the number on the left is less than or equal to the number on the right .

Logical operators:

• Comparison operators usually return single values of true or false.While, logical operators allow you to compare the results of more than one comparison operator.

• (&&) logical and, it tests more than one condition.

• (

  ) logical or , it tests at least one condition.

• ( ! ) logical not , it takes a single boolean value and inverts it .

short circuit evaluation: Logical expressions are evaluated left to right . If the first condition can provide enough information to get the answer, then there is no need to evaluate the second condition.

Loops :

Loops check a condition .if it returns true, a code block will run. Then the condition will be checked again and if it still returns true,the code block will run again . It repeats until the condition returns false.

• There are three types of loops:

  1. For ( to run the code specific number of times, the condition is counter)

  2. While (the code will continue to loop for as long as the condition is true)
  3. Do while (it will always run the statement inside the curly braces at least once even the condition evaluates to false .