Process Control of Python learning

1. If Else

Syntax: if expression1:

Statement1 (s)

Elif expression2:

Statement2 (s)

Else

　　　　Statement3 (s)

2. For

Syntax: for Iterating_var in sequence:

Statements (s)

Where: sequence is a sequence (string, tuple, any one in the list) or dictionary

Example 1:

#!/usr/bin/pythonFruits=['Banana','Apple','Mango'] forIndexinchrange (len (fruits)):Print 'Current fruit:', Furits[index]Print "Good bye!"

Example 2:1 to 100 of cumulative

# !/usr/bin/python num=0 for in range (1,101): num+ =xprint num

extension : Range to quickly generate a sequence

Format: Range (i,j[, step value]) where I default value is 0, stepping value defaults to 1

Example 3: Traversing a dictionary

d={1:111,2:222,5:555,3:333} for in D:  print  d[x] for  in D.items ():    #d.items () returns the Key,value in the dictionary as tuples [(1,111), (2,222), (3,333), (5,555)]  print  k  print V　　    

(1) The contents of Else:else in the For loop are executed only when the For loop is terminated normally, not when the for loop is terminated abnormally

Cases:

# !/usr/bin/python Import  Time  for  in range:  print  x time.sleep (1)  else: 
   
    print
    "
    ending
    "　　
   

(2) Break,continue,pass (code pile, play a role in a placeholder)

3. While

Syntax: while expression:

Statement (s)

Cases:

#!/usr/bin/pythonx="" whilex!="Q":    Print "Hello"x= Raw_input ("Please input something,q for quit:")    if  notX:#if the input is empty, not X is true, jumping out of the loop         BreakElse:    Print "ending ..."  #input q, Loop end, will print this sentence; input blank, not print

Process Control of Python learning