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