# -*- coding:utf-8 -*-

# 第四章 if for while

#布尔逻辑

print True == False

print True and False

print True or False

print not True

print True != False

# if elif else

name = 'lee'

if name == 'chen' :

    print 'yes, you are chen'

elif name == 'le':

    print 'yes, you are god'

elif name == 'shou':

    print 'no, get out'

# 条件表达式, 类似于?表达式

print 'Yes' if 1 + 1 == 2 else 'No'

# for

# range

print help(range)

print type(range(10))

print range(0, 10, 2)

print range(10, 0, -1)

# range(start, stop=None, step=None) step 是每次递增或者递减(-)的step

for i in range(10, 0, -1) :

    print i

for i in ['','','lala'] :

    print i

# while

name = 'chen'

while True :

    print 'heheda'

    if name == 'le' :

        break

    name = 'le'

    continue

    print "no continue"

False

False

True

False

True

Yes

Help on built-in function range in module __builtin__:

range(...)

    range(stop) -> list of integers

    range(start, stop[, step]) -> list of integers

    Return a list containing an arithmetic progression of integers.

    range(i, j) returns [i, i+1, i+2, ..., j-1]; start (!) defaults to 0.

    When step is given, it specifies the increment (or decrement).

    For example, range(4) returns [0, 1, 2, 3].  The end point is omitted!

    These are exactly the valid indices for a list of 4 elements.

None

<type 'list'>

[0, 2, 4, 6, 8]

[10, 9, 8, 7, 6, 5, 4, 3, 2, 1]

10

9

8

7

6

5

4

3

2

1

12

23

lala

heheda

heheda

# while or for else

# 循环正常结束(没有break, return),有else的时候会进入else代码段.

for i in range(10) :

    print i

    if i == 3 :

        break

else :

    print "for else"

0

1

2

3