Python Development "section 4th", "Python branching structure and looping structure"

1. Process Control

　 流程: The order in which the computer executes the code is the process

　　流程控制: The management of the Order of computer code execution is the process control

　　流程分类: Process Control is divided into 3 categories:

• • Sequential structure
  • Branching structure/selection structure
  • Loop structure

2. Branch structure (IF...ELSE)

Multiple branching structures:

#!/usr/bin/python3age = Int (input ("Please enter your dog's Age:")) Print ("") if < 0:    print ("You are kidding me!") elif age = = 1:    print ("the equivalent of 14-year-old person.") ") elif age = = 2:    print (" equivalent to 22-year-old person. ") Elif Age > 2:    human = + (age-2)    print (" corresponding to human Ages: ", Human) # # # Exit Prompt input (" Click the Enter key to exit ")

Nested Branching structures:

#!/usr/bin/python3num=int (Input ("Enter a number:")) if num%2==0:    if num%3==0:        print ("The number you enter can be divisible by 2 and 3")    else:        print ("The number you enter can be divisible by 2, but not divisible by 3") Else:    if num%3==0:        print ("The number you enter can be divisible by 3, but not divisible by 2")    else:        print  ("The number you entered cannot be divisible by 2 and 3")

3, loop structure 3.1, while loop

Format 1: While    conditional expression: The        contents of a loop        [variable change] format 2: While    conditional expression:        The contents of the loop        [variable change]    else:        Python statement:

3.2. For...in cycle

For...in loop is used to iterate over the data of the container class (String, list, tuple, dictionary, collection)

Format 1:    for  variable  in  container:        python code, where you can use variable Format 2:    for variable 1, variable 2 in container:        python code, Variable 1 and variable 2 can be used here

3.3. Else clause

Format:    for  variable  in container:        python code, where you can use the variable    else:        Loop End is the code of execution!

3.4. Break statement

Break effect: Terminates the subsequent operation of the current loop structure

#!/usr/bin/python3for letters in ' Runoob ':     # First Instance   if letter = = ' B ':      break   print (' The current letter is: ', ') var = 1 0                    # Second instance while var > 0:                 print (' When variable value is: ', var)   var = var-1   If var = = 5:      breakprint ("Good bye!")

3.5. Continue statement

Continue effect: Skips the remaining statements in the current loop block and proceeds to the next round of loops.

#!/usr/bin/python3for letters in ' Runoob ':     # First Instance   if letter = = ' O ':        # Skip Output      continue   Print (' Current letters: ', letter) var = ten                    # second instance while var > 0:                 var = var-1   If var = = 5:             # variable is 5 o'clock skip output      Conti Nue   print (' Current variable value: ', var) print ("Good bye!")

3.6. Pass Statement

Pass is an empty statement, in order to maintain the integrity of the program structure, pass does not do anything, generally used as a placeholder statement

def spide ():     Pass if __name__ " __main__ " :    spider ()

Python Development "section 4th", "Python branching structure and looping structure"