python 第二章 快速入门

错误：unindent does not match any outer indentation level

原因：缩进未对齐

self为类实例自身引用，类似C++中this

定义类与实例：

class FooClass(object):

    """my very first class:FooClass"""

    version = 0.1

    # name = 'John Doe'

    def __init__(self,nm='Landry Z'):

        """constructor"""

        self.name = nm  # class instance(data)attribut

        print 'Created a class instance for',nm

    def showname(self):

        """display instance attribute and class name"""

        print 'Your name is',self.name

        print 'My name is',self.__class__.__name__

    def showver(self):

        """display class(static)attribute"""

        print self.version  # references FooClass.version

    def addMe2Me(self,x):

        """apply + operation to argument"""

        return x + x

foo1 = FooClass()

foo1.showname()

foo1.showver()

print foo1.addMe2Me(5)

print foo1.addMe2Me('xyz')

foo2 = FooClass('Lantry')

foo2.showname()

2-4:

word = raw_input('Enter your word:')

print 'This is your enter:%s' % word

wordlen = len(word)

print 'This is length of the enter: %d' % wordlen

2-5:(a)

i = 0

while i <= 10:

    print i,

    i = i + 1

(b)

for i in range(11):

    print i

2-6:

num = raw_input('Enter your number:')

num = int(num)

if num > 0:

    print '正数'

elif num < 0:

    print '负数'

else:

    print 'zero'

2-9:

num = [0,0,0,0]

sum = 0

for i in num:

    i = raw_input('enter the number:')

    sum = float(i)+ sum

print 'the sum is %f' % sum

avg = float(sum) / 4

print 'the avg is %f' % avg

2-11

num = [0,0,0,0,0]

sum = 0

key = 0

def menu():

    print '-' * 20

    print 'Choose number you need:'

    print '(1)求和'

    print '(2)求平均数'

    print '(X)退出'

    print '-' * 20

menu()

key = raw_input('Your choice:')

while key != 'X':

    for i in num:

        i = raw_input('Enter your number:')

        sum = float(sum) + float(i)

    if key == '1':

        print 'The sum is %f' % float(sum)

        menu()

        key = raw_input('Your choice:')

    elif key == '2':

        avg = float(sum) / 5

        print 'The avg is %f' % avg

        menu()

        key = raw_input('Your choice:')

    else:

        print 'Please enter the right number!'

        menu()

        key = raw_input('Your choice:')

2-15:

num = [0,0,0]

sty = 0

flag = 0

i = 0

print "Please enter three number:"

while i < 3:

    num[i] = raw_input()

    i = i + 1

if int(num[0]) < int(num[1]):

    sty = num[0]

    num[0] = num[1]

    num[1] = sty

    print 'one'

    print num

if int(num[0]) < int(num[2]):

    sty = num[0]

    num[0] = num[2]

    num[2] = sty

    print 'two' 

    print num

if int(num[1]) < int(num[2]):

    sty = num[1]

    num[1] = num[2]

    num[2] = sty

    print 'three'

    print num

for i in num:

    print i