用于记录自己写的，或学习期间看到的不错的，小程序，持续更新......
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【例001】计算:1-2+3-4..+199-200值
#encoding=utf-8 #计算 1-2+3-4..+199-200值 #1+3+5+7+...199 #-2-4-6...-200 sum1 = 0 sum2 = 0 for i in range(1,200,2): #计算1+3+5+7...199 sum1 +=i print sum1 for i in range(-200,0,2): #计算-2+(-4)+(-6)...+(-200) sum2 +=i print sum2 print "The total of 1-2+3-4..+199-200 is: ", sum1+sum2
【例002】将两个文件中相同的部分，写到一个文件中
#encoding=utf-8
#Python 2.7.4
#Purpose: 将文件1.txt,2.txt中相同的内容放到3.txt中;
f1 = open("1.txt","r+")
f2 = open("2.txt","r+")
f3 = open("3.txt","w+")
all1 = f1.readlines() #先拿文件1中所有行取出
all2 = f2.readlines() #再拿文件2中所有行取出
f1.close()
f2.close()
for l1 in all1:
for l2 in all2:
if l1.strip()==l2.strip(): #比较行中内容是否一样
f3.write(l2)
else:
continue
else:
pass
print "#"*40
f3.close()
【例003】反向读取文件
假如要读取的test.txt文件内容如下:
Python Perl Java Shell
file1 = file('test.txt','r')
list1 = [] #用一个空列表用于存放每行的内容
while True:
line = file1.readline()
list1.append(line.strip())
if len(line) == 0:
break
for l in list1[::-1]: #反向遍历，然后依次读取出来
print l
file1.close()
Shell Java Perl Python
【例004】 往文件中所有添加指定的前缀
比如文中: print是一个函数
文本文件强制二进制编码
就变成了下面的
01.Python 3.0: #print是一个函数
02.Python 3.0: #文本文件强制二进制编码
#coding = gbk #中文编码
f_r = open('test.txt') #打开要处理文件
f_w = open('file.txt','w') #创建要添加文件
i = 0 #加前缀标志位
while True:
i += 1
line = f_r.readline()
if not line:
break
f_w.write('%02d'%(i) + '.Python 3.0: #' + line)#字符串格式化及拼接技巧
f_r.close() #关闭打开的文件句柄
f_w.close()
【例005】
#coding = gbk
'''''
下面code.txt文件中内容，将
01 CN Chinese
02 IN India
03 HK HongKang
04 JP Japan
05 DE Germany
06 US United States of America
要文件的内容，每一行文件，写到一个文件，且文件名前面两个字段，如
文件名为:01_CN_Chinese.txt
文中内容:01 CN Chinese
知识要点:
1. ''.join 和 split函数
2. 字符的联合
3. with语句,open文件
4. 遍历数组
5. 切片操作
'''
postfix = '.txt' #设置后缀
with open('test.txt') as myfile: #with语句打开文件为myfile
while True: #while循环拿文件读出来
lines = myfile.readlines() #拿所有的行一次性读取到列表中
if not lines: break #没有则中断
for line in lines: #遍历列表
file_out = str('_'.join(line.split()[:])) + postfix #得到01_CN_Chinese.txt文件名
open(file_out,'w').write(line) #write(line),将没行的文件写入新文件中
【例006】
#coding = gbk ''''' #最终实现下面的过程 foos = [1.0, 2.0, 3.0, 4.0, 5.0] bars = [100, 200, 300, 400, 500] 1.0 [200, 300, 400, 500] 2.0 [100, 300, 400, 500] 3.0 [100, 200, 400, 500] 4.0 [100, 200, 300, 500] 5.0 [100, 200, 300, 400] #知识点 1. map函数的理解 2. 关键是切片函数的应用 ''' foos = [1.0, 2.0, 3.0, 4.0, 5.0] bars = [100, 200, 300, 400, 500] def func(foo): index = foos.index(foo) #foo在foos中的索引，拿她取出来 print foo,bars[:][0:index] + bars[:][index+1:] #该索引同样在bars中相同位置，在切片的时候拿它取出，并拼接这个切片 #大功告成！ print map(func,foos)
【例007】求 6! + 5! + 4! + 3! + 2! + 1!
def factorial(n): return reduce(lambda x,y: x* y, range(1,n+1))#求6! print reduce(lambda x,y: x + y, [factorial(i) for i in range(1,6)]) #求6! + 5! + 4! + 3! + 2! + 1!
【例008】 根据输入打印文件
import sys
helpinfo= '''''\
This program prints files to the standard output.
Any number of files can be specified.
Options include:
--[version|VERSION|V|v]: Prints the version number
--[help |HELP |H|h]: Display the help
'''
def readfile(filename):
try:
f = open(filename)
while True:
line = f.readline()
if not line:
break
print line,
except:
print 'some error here'
if len(sys.argv) < 2:
print 'No action is needed!'
sys.exit()
if sys.argv[1].startswith('--'):
option = sys.argv[1][2:]
if option in ['version','v','V','VERSION']:
print 'Version 1.0'
elif option in ['h','H','help','HELP']:
print helpinfo
else:
print 'Unknown option.'
sys.exit()
else:
for filename in sys.argv[1:]:
readfile(filename)
【例009】函数中args的用法
def powersum(power,*args): '''''Print each argument's power''' total = 0 for item in args: total += pow(item,power) return total print powersum(2,3,4) # (3**2) + (4**2) print powersum(2,10) # 10**2 print powersum(2) # 0**2
【例010】匿名函数作为返回值
def repeater(n):
print n
return lambda s: s*n
twice = repeater(2)
print twice('Hello')
print twice(5)
#!/usr/bin/env python
import os,time
source = ['/home/test/C','/home/test/shell'] #源文件目录
target_dir = '/home/test/python' #目标文件目录
today = target_dir + time.strftime('%Y%m%d') #
now = time.strftime('%H%M%S')
if not os.path.exists(today): #判断目录是否存在
os.mkdir(today) #不存在的话则新建
print 'Successfully created directory', today
target = today + os.sep + now + '.zip' #target文件格式
zip_cmd = "zip -qr '%s' %s" % (target, ' '.join(source)) #-q:安静模式 -r递归模式
#等价于 zip -qr /home/test/python20141202/142151.zip /home/test/C /home/test/shell
if os.system(zip_cmd) == 0: #判断命令是否成功执行，成功执行，返回0
print 'Successful back to:', target
else: #失败的话，打印信息
print 'Backup FAILED.'
加comment的版本
#!/usr/bin/env python
import os,time
source = ['/home/test/C','/home/test/shell']
target_dir = '/home/test/python'
today = target_dir + time.strftime('%Y%m%d')
now = time.strftime('%H%M%S')
comment = raw_input('Enter comments here-->') #要输入的comment
if len(comment) == 0: #如果没有comment
target = today + os.sep + now + '.zip' #按照上面的操作执行
else:
target = today + os.sep + now + '_' + comment.replace(' ','_') + '.zip'
#如果有comment,
if not os.path.exists(today):
os.mkdir(today)
print 'The backup directory created!', today
zip_command = "zip -qr '%s' %s" % (target, ' '.join(source))
if os.system(zip_command) == 0:
print 'Scuccessful backup to', target
else:
print 'The backup FAILED'
输出结果 ：
# python backup_ver4.py Enter comments here-->add new example The backup directory created! /home/test/python20141202 Scuccessful backup to /home/test/python20141202/145130_add_new_example.zip
【例012】将二进制数转为10进制数
def func(B):
I = 0
while B:
I = I * 2 + (ord(B[0])-ord('0'))
B = B[1:]
return I
b = raw_input('Enter binary here:')
print func(b)
def find_duplicate(lst):
tmp = [] #临时变量，存放排除后的列表
for item in lst:
if not item in tmp: #将不在tmp变量找出
tmp.append(item)
else:
print 'The duplicate item is:', item
print 'After remove the duplicate item:',
return tmp
if __name__=='__main__':
test = input("Enter List here:") #input技巧
print find_duplicate(test)
>>>
Enter List here:[2,1,4,2]
The duplicate item is: 2
After remove the duplicate item: [2, 1, 4]
【例014】用Python中列表中append()，pop()函数实现简单的堆栈方法:后进先出
l = [] l.append(1) l.append(2) l.append(3) print l print l.pop() print l.pop() print l.pop()
>>> words = ['apple','bat','bar','book','atom']
>>> tmp = {} #建个空字典
>>> for word in words:
letter = word[0] #作为字典中的键
if letter not in tmp: #判断首字母是否存在于字典
tmp[letter] = [word] #注意要添加[],很关键
else:
tmp[letter].append(word) #如果键已经存在，值列表添加
>>> tmp
{'a': ['apple', 'atom'], 'b': ['bat', 'bar', 'book']}
【例016】对文件进行整理（除空格、TAB键、除#!&?等键），假如文本文件全为人名，并让首字母大写
john black Jerry! &alice TOm# south carolina### mr smith?
import re
def clean(strings):
result = []
for value in strings:
value = value.strip()
value = re.sub('[#!&?]','',value)
value = value.title()
result.append(value)
return result
with open('data.txt','a+') as myfile:
lines = myfile.readlines()
for line in clean(lines):
print line
>>>
John Black
Jerry
Alice
Tom
South Carolina
Mr Smith
【例017】用while循环来判断某个数是否是质数
y = input('Enter a integer Here:')
x = y / 2
while x > 1:
if y % x == 0:
print y, 'has factor', x
break
x -= 1
else:
print y, 'is prime'
names = ['Tom','Alice','Wendy','Jerry','Bob','Smith'] while names: if names[0] == 'Jerry': print 'Hi,', names[0] break names = names[1:] else: print 'Not Found!'
【例019】对嵌套的序列进行处理
>>> T = ((1,2),(3,4),(5,6)) >>> for (a,b) in T: ... print a+100, b+200 ... 101 202 103 204 105 206
source = ['sting',(3,4),100,0.1,[1,2]] tests = [(3,4),3.14] for t in tests: #先是遍历小循环 for s in source: #再遍历外层循环 if s == t: print t, 'Found it! ' break else: #else语句的位置非常关键， print t, 'Not Found!'
等价于下面这种方式
source = ['sting',(3,4),100,0.1,[1,2]] tests = [(3,4),100,3.14] for t in tests: if t in source: print t, 'Found it.' else: print t, 'Not found.'
【例021】用for循环来收集两个序列中相同的部分
seq1 = 'spam' seq2 = 'suck' res = [] for s1 in seq1: if s1 in seq2: res.append(s1) print res
【例022】隔个取出字符串
S = 'abcdefghijklmn' for i in range(0,len(S),2): print S[i], #或者 print S[::2]
【例023】两个列表，列表中每个元素加100，然后与L1中对应元素相乘，形成列表，再对列表求和
L1 = [1,2,3,4] L2 = [5,6,7,8] #L2每个元素加一百,105,106,107 #(5+100)*1 + (6+100)*2 + (100+7)*3 + (100+8)*4 # 合计: 1070 L3 = [x+100 for x in L2] L4 = [] for (x,y) in zip(L1,L3): L4.append(x*y) print sum(L4) #或者用下面精简方式，只是刚看到有点头痛! print sum([x*y for x,y in [T for T in zip(L1,[x+100 for x in L2])]])
【例024】对列表进行，合并，去重，取交集等操作
def func(seq1, seq2=None, opra=None): res = [] if opra == '-': for item1 in seq1: if item1 not in seq2: res.append(item1) elif opra == '&': for item1 in seq1: if item1 in seq2: res.append(item1) elif opra == '|': tmp = seq1[:] for item1 in seq2: if item1 not in seq1: tmp.append(item1) return tmp elif opra == '^': for i in seq1: if i not in seq2: res.append(i) for i in seq2: if i not in seq1: res.append(i) return res else: print 'Need list as input!' return res L1 = [1,2,3,4] L2 = [3,4,5,6] print '[L1 - L2]:',func(L1,L2,'-') print '[L1 & L2]:',func(L1,L2,'&') print '[L1 | L2]:',func(L1,L2,'|') print '[L1 ^ L2]:',func(L1,L2,'^') def list_remove(seq): res = [] for i in seq: if i not in res: res.append(i) return res L1 = [3,1,2,3,8] print list_remove(L1) def find_duplicate(seq): res = [] for i in range(len(seq)): if seq.count(seq[i]) >= 2: print 'Found %s'% seq[i], 'The index is:', i res.append(seq[i]) return res L1 = [3,1,2,3,8] print find_duplicate(L1)
结果如下:
>>> [L1 - L2]: [1, 2] [L1 & L2]: [3, 4] [L1 | L2]: [1, 2, 3, 4, 5, 6] [L1 ^ L2]: [1, 2, 5, 6] [3, 1, 2, 8] Found 3 The index is: 0 Found 3 The index is: 3 [3, 3]
【例025】通过函数改变全局变量的三种方式
var = 99 def local(): var = 0 def glob1(): global var var += 1 def glob2(): var = 0 import Learn Learn.var += 1 def glob3(): var = 0 import sys glob = sys.modules['Learn'] glob.var += 1 def test(): print var local();glob1();glob2();glob3() print var
【例026】求range(10)中每个元素的立方
def func(): res = [] for i in range(10): res.append(lambda x, i=i: i ** x) #i=i这是关键，否则i默认记忆最后一个值:9 return res >>> res = func() >>> for i in range(10): res[i](3) 0 1 8 27 64 125 216 343 512 729
【例027】求最小值
def min1(*args):
mini = args[0]
for arg in args[1:]:
if arg < mini:
mini = arg
return mini
def min2(first,*rest):
mini = first
for arg in rest:
if arg < first:
mini = arg
return mini
def min3(*args):
res = list(args)
res.sort()
return res[0]
print min1('c','a','b')
print min2(3,1,4)
print min3(1,'a',78,'c')
def func(test, *args):
res = args[0]
for arg in args[1:]:
if test(arg, res):
res = arg
return res
def lessthan(x, y): return x < y
def morethan(x, y): return x > y
print func(lessthan, 4,3,1,2,9)
print func(morethan, 4,3,1,2,9)
【例028】求多个集合的交集及合集
def intersect(*args):
res = []
for x in args[0]:
for other in args[1:]:
if x not in other:
break
else:
res.append(x)
return set(res) #去除重复的部分
print intersect('SPAM','SCAM','SLAM')
def union(*args):
res = []
for seq in args:
for item in seq:
if not item in res:
res.append(item)
return res
print union('SA','SB','SC')
def intersect(*args):
res = []
for x in args[0]:
for other in args[1:]:
if x not in other:
break
else:
res.append(x)
#为了交互['S','S','A','A','M','M']
tmp = []
[tmp.append(i) for i in res if i not in tmp]
return tmp
print intersect('SCAM','SPAM','SLAM')
【例029】字典的拷贝及添加
def copyDict(old):
new = {}
for key in old:
new[key] = old[key]
return new
def addDict(d1,d2):
new = {}
for key in d1.keys():
new[key] = d1[key]
for key in d2:
new[key] = d2[key]
return new
【例030】求质数
def isPrime(y): if y < 1: print y, 'not prime' else: x = y // 2 while x>1: if y % x == 0: print y, 'has factor', x break x -= 1 else: print y, 'is prime!'
【例031】比较多个值的大小
def min_max(func,*args): res = args[0] for arg in args[1:]: if func(arg,res): res = arg return res def min_func(x,y): return x < y def max_func(x,y): return x > y if __name__=='__main__': print "The min value is:", min_max(min_func,4,3,2,1,7,6,9) print "The max value is:", min_max(max_func,4,3,2,1,7,6,9) # 输出结果: >>> The min value is: 1 The max value is: 9
【例032】写一个小函数实现内置函数dir的功能
#Filename: mydir.py tag = 1 def listing(module): if tag: print '-'*30 print 'name:', module.__name__,'file:', module.__file__ print '-'*30 count = 0 for attr in module.__dict__.keys(): if attr[0:2] == '__': print '%02d) %s' % (count, attr) else: print getattr(module,attr) count = count + 1 if tag: print '-'*30 print module.__name__, 'has %d names.' % count print '-'*30 if __name__=='__main__': import mydir listing(mydir)
【例033】求分数平均值
'''''Filename: grades.txt 求该文件中第二列的平均值
Jerry 78
Alice 45
Wendy 96
Tom 56
Bob 85
'''
temp = []
for line in open('grades.txt'):
a = line.strip().split()
if a:
temp.append(a[1])
#['78', '45', '96', '56', '85']
total = 0
for i in temp:
total += int(i)
print 'The total grade is:', total, 'The average is:', total/len(tmp)
【例034】一个实际类的例子
class GenericDisplay:
def gatherAttrs(self):
attrs = '\n'
for key in self.__dict__:
attrs += '\t%s=%s\n' % (key, self.__dict__[key])
return attrs
def __str__(self):
return '<%s: %s>' % (self.__class__.__name__, self.gatherAttrs())
class Person(GenericDisplay):
def __init__(self, name, age):
self.name = name
self.age = age
def lastName(self):
return self.name.split()[-1]
def birthDay(self):
self.age += 1
class Employee(Person):
def __init__(self, name, age, job=None, pay=0):
Person.__init__(self, name, age)
self.job = job
self.pay = pay
def birthDay(self):
self.age += 2
def giveRaise(self, percent):
self.pay *= (1.0 + percent)
if __name__ == '__main__':
bob = Person('Bob Smith', 40)
print bob
print bob.lastName()
bob.birthDay()
print bob
sue = Employee('Sue Jones', 44, job='dev', pay=100000)
print sue
print sue.lastName
sue.birthDay()
sue.giveRaise(.10)
print sue
【例035】根据给定的年月日以数字方式打印出日期(February 27th, 2015)
# coding = UTF-8
#根据给定的年月日以数字形式打印出日期
months = [
'January' ,
'February',
'March' ,
'April' ,
'May' ,
'June' ,
'July' ,
'August' ,
'September',
'October' ,
'November' ,
'December'
]
#以1~31的数字作为结尾的列表
endings = ['st','nd','rd'] + 17 * ['th'] + \
['st','nd','rd'] + 07 * ['th'] + \
['st']
year = raw_input('Year: ')
month = raw_input('Month(1-12): ')
day = raw_input('Day(1-31): ')
month_number = int(month)
day_number = int(day)
#月份和天数减1来获得正确的索引
month_name = months[month_number - 1]
ordinal = day + endings[day_number - 1]
print month_name + ' ' + ordinal + ', ' + year
#输出结果
>>>
Year: 2015
Month(1-12): 2
Day(1-31): 27
February 27th, 2015
【例036】在居中的盒子里打印一条语句
sentence = raw_input("Sentence: ")
screen_width = 80
text_width = len(sentence)
box_width = text_width + 6
left_margin = (screen_width - box_width) // 2
print
print ' '*left_margin + '+' + '-'*(box_width-4) + '+'
print ' '*left_margin + '| ' + ' '*(text_width) +' |'
print ' '*left_margin + '| ' + sentence +' |'
print ' '*left_margin + '| ' + ' '*(text_width) +' |'
print ' '*left_margin + '+' + '-'*(box_width-4) + '+'
print
#输出结果
>>>
Sentence: Welcome To Beijing!
+---------------------+
| |
| Welcome To Beijing! |
| |
+---------------------+
【例037】简单小数据库验证
database = [
['Bob', '1234'],
['Tom', '2345'],
['Foo', '1478']
]
usr = raw_input('Enter username: ')
pwd = raw_input('Enter password: ')
if [usr, pwd] in database:
print 'Access Granted!'
else:
print 'Access Deny!'
【例038】使用给定的宽度打印格式化后的价格列表
width = input('Please enter width: ')
price_width = 10
item_width = width - price_width
header_format = '%-*s%*s'
format = '%-*s%*.2f'
print '=' * width
print header_format % (item_width, 'Item', price_width, 'Price')
print '-' * width
print format % (item_width, 'Apples', price_width, 0.4)
print format % (item_width, 'Sweets', price_width, 0.5)
print format % (item_width, 'Pepper', price_width, 12.94)
print format % (item_width, 'Tender', price_width, 42)
print '-' * width
输出格式:
>>> Please enter width: 30 ============================== Item Price ------------------------------ Apples 0.40 Sweets 0.50 Pepper 12.94 Tender 42.00 ------------------------------
【例039】遍历两个对应列表
names = ['Alice', 'Bob' , 'Cherry', 'David'] numbers = ['0000' , '1111', '2222' , '3333' ] for index,name in enumerate(names): print '%-7s=> %s' % (name, numbers[index]) #输出结果 >>> Alice => 0000 Bob => 1111 Cherry => 2222 David => 3333
当然也可以采用如下通常的做法:
names = ['Alice','Bob', 'John', 'Fred'] ages = [27, 23, 31, 29] for i in range(len(ages)): print names[i],' is ', ages[i], ' years old!' #输出结果: >>> Alice is 27 years old! Bob is 23 years old! John is 31 years old! Fred is 29 years old!
【例040】对存储在小字典中数据进行查询
peoples = {
'Alice':{
'phone' : '0948',
'address' : 'aaaa'
},
'Wendy':{
'phone' : '4562',
'address' : 'bbbb'
},
'David':{
'phone' : '4562',
'address' : 'bbbb'
}
}
#字典使用人名作为键。每个人用另外一个字典来表示，其键'phone'和'addr'分别表示他们的电话号码和地址
labels = {
'phone' : 'phone number',
'address' : 'address'
}
#针对电话号码和地址使用描述性标签，会在打印输出时用到。
key = ''
name = raw_input('Name: ')
if name in peoples:
request = raw_input('Enter (p) or (a): ')
if request == 'p':
key = 'phone'
elif request == 'a':
key = 'address'
else:
print 'Please input p(phone) an a(address)!'
print "%s's %s is %s" % (name, labels[key],peoples[name][key])
else:
print 'Not Found!'
或者使用字典的get()方法，更好些。完整代码如下:
#字典使用人名作为键。每个人用另外一个字典来表示，其键'phone'和'addr'分别表示他们的电话号码和地址
peoples = {
'Alice':{
'phone' : '0948',
'address' : 'aaaa'
},
'Wendy':{
'phone' : '4562',
'address' : 'bbbb'
},
'David':{
'phone' : '4562',
'address' : 'bbbb'
}
}
#针对电话号码和地址使用描述性标签，会在打印输出时用到。
labels = {
'phone' : 'phone number',
'addr' : 'address'
}
name = raw_input('Name: ')
#查找电话号码还是地址?
request = raw_input('Phone number (p) or address (a)? ')
#查找正确的键
key = request #如果请求即不是p也不是a
if request == 'p': key = 'phone'
if request == 'a': key = 'addr'
#使用get()函数提供默认值
person = peoples.get(name,{})
label = labels.get(key, key)
result = person.get(key, 'not available')
print "%s's %s is %s." % (name, label, result)
【例041】字典格式化字符串例子
template='''''<html>
<head><title></title></head>
<h1>%(title)s</h1>
<p1>%(text)s</p1>
<body></body>
</html>'''
data = {'title':'My Home Page','text':'Welcome to my home page!'}
print template % data
#输出结果:
>>>
<html>
<head><title></title></head>
<h1>My Home Page</h1>
<p1>Welcome to my home page!</p1>
<body></body>
</html>
【例042】需找100以内的最大平方数
from math import sqrt #从100开始往下找，找到即停止，最大为: 81 for n in range(99, 0, -1): root = sqrt(n) if root == int(root): print n break
【例043】用while/True, break控制输入
while True: #一直进行下去，除非break
word = raw_input('Please Enter a word: ')
if not word: break #输入为空的话，中断循环
print 'The word was: ' + word
#将两个列表中首字母相同的罗列在一起 girls = ['alice', 'bernice', 'clarice'] boys = ['chris', 'arnold', 'bob'] #列表推导: print [b+'+'+g for b in boys for g in girls if b[0] == g[0]] #输出结果: >>> ['chris+clarice', 'arnold+alice', 'bob+bernice']
【例045】斐波那契数列求指定数字的列表
def fibs(x):
fibs = [0, 1] # 初始值
for i in range(x):
# fibs[-2]+fibs[-1]：最新一个值是前面两个值之和
# 并用append方法将其添加在后面
fibs.append(fibs[-2]+fibs[-1])
print fibs
if __name__=='__main__':
num = input('How many Fibonacci numbers do you want? ')
fibs(num)
或者用普通方法实现:
>>> def fib(max): n, a, b = 0, 0, 1 tmp_list = [] while n < max: tmp_list.append(a) a, b = b, a+b n += 1 return tmp_list >>> fib(8) [0, 1, 1, 2, 3, 5, 8, 13]
【例046】写一个自定义列表类，让它支持尽可能多的支持操作符号
class MyList:
def __init__(self, start):
self.wrapped = [] # Make sure it's a list here
for x in start:
self.wrapped.append(x)
def __add__(self, other):
return MyList(self.wrapped + other)
def __mul__(self, time):
return MyList(self.wrapped * time)
def __getitem__(self, offset):
return self.wrapped[offset]
def __len__(self):
return len(self.wrapped)
def __getslice__(self, low, high):
return MyList(self.wrapped[low:high])
def append(self, node):
self.wrapped.append(node)
def __getattr__(self, name): # Other members: sort/reverse/etc
return getattr(self.wrapped, name)
def __repr__(self):
return repr(self.wrapped)
if __name__ == '__main__':
x = MyList('spam')
print x
print x[2]
print x[1:]
print x + ['eggs']
print x * 3
x.append('a')
x.sort()
for c in x:
print c,
# 输出结果如下:
>>>
['s', 'p', 'a', 'm']
a
['p', 'a', 'm']
['s', 'p', 'a', 'm', 'eggs']
['s', 'p', 'a', 'm', 's', 'p', 'a', 'm', 's', 'p', 'a', 'm']
a a m p s
【例047】用urllib模块来批量下载图片
import re
import urllib
def getHtml(url):
page = urllib.urlopen(url)
html = page.read()
return html
def getImg(html):
reg = r'src="(.*?\.jpg)" width'
imgre = re.compile(reg)
imgList = re.findall(imgre, html)
x = 0
for imgurl in imgList:
urllib.urlretrieve(imgurl, '%s.img' % x) # urlretrieve()下载图片
x += 1
html = getHtml("http://www.w3cschool.cc/")
print getImg(html)
【例048】用PyQt4实现简单的按钮事件（Hello,World!）
# -*- coding: utf-8 -*-
import sys
from PyQt4 import QtCore, QtGui
# 自定义的窗口类
class TestWindow(QtGui.QWidget):
# 窗口初始化
def __init__(self, parent = None):
super(TestWindow, self).__init__(parent)
self.setWindowTitle(u'胡桃夹子')
# 创建按钮
self.pushButton = QtGui.QPushButton(u'测试按钮')
# 创建文本框
self.textEdit = QtGui.QTextEdit()
# 创建垂直布局
layout = QtGui.QVBoxLayout()
# 将控件添加到布局中
layout.addWidget(self.textEdit)
layout.addWidget(self.pushButton)
# 设置窗口布局
self.setLayout(layout)
# 设置按钮单击动作
self.pushButton.clicked.connect(self.sayHello)
# 按钮动作处理
def sayHello(self):
self.textEdit.setText('Hello World!')
# 程序主入口
if __name__=='__main__':
app = QtGui.QApplication(sys.argv)
mainWindow = TestWindow()
mainWindow.show()
sys.exit(app.exec_())
【例049】用python解析文本的一个例子
假如配置文件如下, 要确保配置文件行为tablename后面的level中值给读取出来
#FileName: data.conf (tablename "A__employee__id.sql") (userid "000001") (number "100001") (level "P1") (tablename "B__employee__id.sql") (userid "100001") (number "100000") (level "P2") (tablename "C_other_table.sql") (userid "000001") (number "100001") (level "P2") (tablename "C__employee__table.sql") (userid "000001") (number "100001") (level "P3")
代码如下:
def parse_File(filename):
tmp = []
fh = open(filename)
line = fh.readline()
flag = 0
while line:
if "tablename" in line and "__employee__" in line:
count = 0
flag = 1
if flag == 1:
count += 1
if count == 4 and "level" in line:
value = line.split(r'"')[1]
tmp.append(value)
line = fh.readline()
return tmp
if __name__ == '__main__':
print parse_File('data.conf')