در این بخش در مورد if , while , for صحبت می کنیم

1. PYTHON FOR ETHICAL HACKERS
Mohammad reza Kamalifard

2. Python Language Essentials
Part 4 :
Conditional Statements

3. if Statement
Like if in other languages but second if called elif
if test_condition1:
do stuff
do stuff
elif test_condition2:
do stuff
do stuff
elif test_condition3:
do stuff
do stuff
else:
do stuff

4. Python Indentation
• Python uses whitespace indentation, rather than curly braces
or keywords, to delimit blocks; a feature also termed the off-
side rule.
• An increase in indentation comes after certain statements; a
decrease in indentation signifies the end of the current block.

5. C, C++
#include <iostream>
using namespace std;
int main(){
cout<<"Hello, World!";
return 0;
}

6. C, C++
#include <iostream>
using namespace std;int
main(){cout<<"Hello,World!";return 0;}

7. Indentation
if name == 'ali':
print 'Your name is ali'
Print ‘Always print this line‘
• 4 space
• Tab
• Google use 2 space
• We use 4 space (PEP 8)

8. $ vim if_statement.py
#!/usr/bin/env python
name = raw_input('Please Enter Your name! : ')
if name == 'reza':
print 'You are reza'
print 'And a course instructor'
elif name == 'Arman':
print 'You are Arman'
print 'And a student'
else:
print 'I don't know you‘
~
~
~

9. $ chmod a+x if_statement.py
$ ./if_statement.py
Please Enter Your name! : reza
You are reza
And a course instructor
$
$ ./if_statement.py
Please Enter Your name! : ali
I don’t know you
$
$ ./if_statement.py
Please Enter Your name! : Arman
You are Arman
And a student
$

10. While Loops
while statement_is_true:
do stuff
do stuff
break : get out if innermost loop
continue : start the next pass of the innermost
pass : do nothing, placeholder

11. $ vim while_statement.py
#!/usr/bin/env python
age = int(raw_input('Please Enter Your age ? : '))
while age > 10:
print 'You age is grater than 10'
~
~
~

12. $ chmod a+x while_statement.py
$ ./ while_statement.py
Please Enter Your age ? : 23
You age is grater than 10
You age is grater than 10
You age is grater than 10
You age is grater than 10
You age is grater than 10
You age is grater than 10
You age is grater than 10
You age is grater than 10
You age is grater than 10
You age is grater than 10
You age is grater than 10
You age is grater than 10
You age is grater than 10
You age is grater than 10
You age is grater than 10
You age is grater than 10

13. $ vim while_statement.py
#!/usr/bin/env python
age = 20
while age > 10:
age = int(raw_input('Please Enter Your age ? : '))
print 'You age is grater than 10'
~
~
~

14. $ chmod a+x while_statement.py
$ ./ while_statement.py
Please Enter Your age ? : 23
You age is grater than 10
Please Enter Your age ? : 15
You age is grater than 10
Please Enter Your age ? : 18
You age is grater than 10
Please Enter Your age ? : 8
You age is grater than 10
$

15. $ vim while_statement.py
#!/usr/bin/env python
age = 20
while age > 10:
age = int(raw_input('Please Enter Your age ? : '))
if age > 10:
print 'Your age is grater than 10'
elif age < 10:
print 'Your age is smaller than 10'
else:
print 'Your age is equal to 10'
~
~

16. $ chmod a+x while_statement.py
$ ./ while_statement.py
Please Enter Your age ? : 23
You age is grater than 10
Please Enter Your age ? : 15
You age is grater than 10
Please Enter Your age ? : 8
You age is smaller than 10
$
$ ./ while_statement.py
Please Enter Your age ? : 17
You age is grater than 10
Please Enter Your age ? : 10
You age is equal to 10
$

17. For Loops
for item in object:
do stuff
do stuff
for item in [1, 2, 3]
for item in ['a', 2, '3']
for (x,y) in [('reza', 23), ('mohammad', 25)]

18. >>> for item in [1, 2, 3]:
... print item
...
1
2
3

19. item is a name can be anything
>>> names = ['Reza', 'Majid', 'Sara', 'Iman']
>>> names
['Reza', 'Majid', 'Sara', 'Iman']
>>> for name in names:
... print name
...
Reza
Majid
Sara
Iman
>>>

20. >>> info = [('Reza', 23), ('Sara', 20), ('Shayan', 30),
('AmirAli', 21)]
>>> info
[('Reza', 23), ('Sara', 20), ('Shayan', 30), ('AmirAli', 21)]
>>> for (name, age) in info:
... print 'Your name is : %s and Your age is %d' % (name,
age)
...
Your name is : Reza and Your age is 23
Your name is : Sara and Your age is 20
Your name is : Shayan and Your age is 30
Your name is : AmirAli and Your age is 21
>>>

21. Emulating C style for loops
C style loops : for(i=0; i<10; i++)
for(i=0; i<10; i++){
cout<<i<<',';
}
0,1,2,3,4,5,6,7,8,9,

22. range()
range(lower, upper, step)
create a list for use
range(n) – [0,...,n-1]
>>> range(10)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>>

23. >>> range(1,10)
[1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> range(1,10,2)
[1, 3, 5, 7, 9]
>>>
>>> for number in range(1,10,2):
... print number
...
1
3
5
7
9
>>>

24. References
• Data model — Python v2.7.5 documentation
• http://docs.python.org/2/reference/datamodel.html#objects-values-and-types
• PEP 8 -- Style Guide for Python Code
• http://www.python.org/dev/peps/pep-0008/
THIS IS A COPYRIGHTED MATERIAL
©2013 Mohammad Reza Kamalifard.
ALL RIGHTS RESERVED.