Week 4 - Programming patterns across languages & using pass, flag, break

Liaw Bei Le · April 13, 2021

Learning   Python   Practices   Reflections
  1. Programming patterns
  2. Using pass in custom functions
  3. Using a flag & break in a for loop

Then, I did some practice problems.

What I learnt:

1. Programming Patterns:

  • Different Programming Languages have different syntax.
    • Syntax: Language-specific code rules.
  • But they all have some common themes: print, loops, function
  • Programming Patterns are good ways to write code across diffferent languages
    • Example:
      • Python: 
          for something in some_list:
  print(something)
  def func():
  print("hello")
      • Java: structs, switch-cases 
          for(int i=0; i<10; i++){
  System.out.println(i)
  }
  public static void main():{
  System.out.println()
  }

    1a. How to sum values in a list
    declare variable sum
    loop through list
    sum=sum+item

    1b. Check if item meets condition
    loop through a list
    if conditional is true (if statement)
    then do something
    or do something else

    1c. Flag
    set flag to default value
    loop through list
    if condition is true
    then set flag
    exit loop
    if flag is set
    do something
    or do something else

    1d. Minimum or max of a list

2. Using pass

  • when creating a custom function without typing in its code/function at first -
    to prevent errors, in case custom function is incomplete 
    number_input=int(input("Number: "))
def check_prime(the_number):
  pass
check_prime(number_input)

3. Using a flag and break in a for loop

Practices

  • Create a function to check if a number is a prime 
    '''Use flag, use range( )'''
'''Get number input. Set flag=0 by default, if number is not prime, flag=1 and break'''  
'''(so that program stops checking other numbers after that within the range).'''
def check_prime(the_number):
  flag=0
  for number in range(2,the_number):
      if the_number%number==0:
          flag=1
          break
  if flag==0:
      print("Number is prime")
  else:
      print("Number is not prime")
number_input=int(input("Number: "))
check_prime(number_input)

More Other Practices

  • Create a function to generate a list of all the factors of a number 
    '''use range( ), use list.append( ) to an empty list'''
def factor_list(inserted_number):
  list_of_factors=[]
  for number in range(1,inserted_number+1):
      if inserted_number%number==0:
          list_of_factors.append(number)
  print(list_of_factors)
number_input=int(input("Number: "))
factor_list(number_input)

Thoughts

It’s great to learn about some of the good coding practices and learning Python definitely would make learning other languages in the future easier for me!

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