جریان کنترلی (بخش دوم: حلقه های تکرار) در پایتون

حلقۀfor

for var in iterable:
 # loop body using var
else:
 #invoked if no "break"

>>> for letter in "python" :
        print letter



p
y
t
h
o
n

لیست: 

>>> for veg in ['Celery', 'Mushroom', 'Okra’]: 
         print veg
Celery 
Mushroom 
Okra

لیست در پایتون 

>>>  A = [(1,2), (3,4), (5,6)]
(x, y) in A: print X,
>>> for (x, y) in A: print X,y, ,--> (,x,’,’y,’)’
1 2 → (1,2)
3 4 → (3, 4 )
5 6 → (5,6 )

>>> A = [(1,2), (3,4), (5,6)]
>>> for i inA:
print i

(1, 2)
(3, 4)
(5, 6)

>>> for i, s in enumerate ([,kitchen', 'living room']):
 print (i, s )
O kitchen
1 living room
2 dining room

>>> question = 'first name', 'last name', 'favorite color' )
>>> answer = [ " Peter " , "Mandela " , "yellow" )
>>> for q, a in Zip (question, answer) :
 print "what is your {0}? it's {1} . ". format (g, a)
what is your first name? it's Peter.
 what is your last name? it's Mandela. 
what is your favorite color? it's yellow.

>>> f = open ( ‘C:\Python 27 \spam... txt ‘ ) 
>>> for line in f:
print line
this is the first line
this is the second line
this is the third line

>>> d = { ‘key1’ : ‘ value1', 'key2’ : ‘ value2’} 
>>> for k, V in d. items () :
 print (k, W)
(‘key2', 'value2’)
 (‘key1', 'value1’)

تابع range

>>> range ( 7 ) , range(2, 7), range(0, 7, 2)
([0, 1, 2, 3,4, 5, 6], [2, 3, 4, 5, 6], [0, 2, 4, 6])
[0, 2, 4, 6]



>>> for i in range (2) : 
print i, (" Hello world")
O Hello World 
1 Hello World

>>> for mult in range (4, 7) : #Run 3 iteration, 4, 5, and 6
 for i in range (1,11) : 
print i, 'x' , mult, ‘=’ , i* mult 
print










1*4=4
2*4=8
3*4=12
4*4=16
5*4=20
6*4=24
7*4=28
8*4=32
9*4=36
10*4=40

1*5=5
2*5=10
3*5=15
4*5=20
5*5=25
6*5=30
7*5=35
8*5=40
9*5=45
10*5=50

1*6=6
2*6=12
3*6=18
4*6=24
5*6=30
6*6=36
7*6=42
8*6=48
9*6=54
10*6=60

حلقه while

>>> X = 0
>>> y = 5
>>> while x < y : print X
 x += 1

0
1
2
3
4

while : #must evaluate to true to continue 

else: # optional 
 #run in absence of ‘boreak’

حلقه بی نهایت

>>> while True:
        print (‘python’)
Python 
Python 
Python 
Python 
Python 
Python 
Python 
Python
Traceback (most recent call last): 
File "", line 2, in  
print (‘Python') 
File “C :\python27\lib\idlelib\PyShell.py”,line 1356, in writre
   return self.shell.write(s , self.tags)
keyboardInterrupt

مقایسۀ حلقه‌های for و while

>>> for i in range (1,3) : printe i 
1
2

>>> for i in range(1,3) : print ‘the value is:’; print i
The value is:
1
The value is:
2
>>>
>>>
>>> for i in range(1,3):
       print 'the value is:’
       print i
The value is:
1
The value is:
2



>>> for i in range(1,3): print 'the value is:\n i'
the value is:
i
the value is:
i

دستورات break و continue

While :

if :
   break #exit loop, exit else
if :
   continue #go to test1
Else:
    #processed if no "break"

>>> a = 0
>>> while a<13:
         a +=1
         If a ==5:
                  Continue
         If a ==10:
			Break
         Print a
1
2
3
4
5
6
7
8
9