Skip to content

6.4/5 Variables and Parameters are Local

  • An assignment statement in a function creates a local variable
  • It is called local because this variable only exists inside the function and you cannot use it outside.
  • it is legal for a function to access a global variable. However, this is considered bad form by nearly all programmers and should be avoided.
  • Local Variables
    • Python looks at the variables that are defined as local variables in the function. We call this the local scope
  • Global Variables
    • If the variable name is not found in the local scope, then Python looks at the global variables, or global scope

6.5 The Accumulator Pattern

  • This pattern of iterating the updating of a variable is commonly referred to as the accumulator pattern
  • We refer to the variable as the accumulator
  • Remember that the key to making it work successfully is to be sure to initialize the variable before you start the iteration.
  • Once inside the iteration, it is required that you update the accumulator.

Main use case

initialize the accumulator variable
repeat:
    modify the accumulator variable

# when the loop terminates the accumulator has the correct value