自己使用总结Python程序代码片段
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
复制代码 代码如下:
#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
复制代码 代码如下:
#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:
复制代码 代码如下:
Python
Perl
Java
Shell
实现代码:
复制代码 代码如下:
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()
输出结果:
复制代码 代码如下:
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
复制代码 代码如下:
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】
复制代码 代码如下:
#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】
复制代码 代码如下:
#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!
复制代码 代码如下:
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
复制代码 代码如下:
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
复制代码 代码如下:
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
复制代码 代码如下:
def repeater(n):
print n
return lambda s: s*n
twice = repeater(2)
print twice(\’Hello\’)
print twice(5)
【例011】备份程序
复制代码 代码如下:
#!/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
复制代码 代码如下:
#!/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 ：
复制代码 代码如下:
# 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
复制代码 代码如下:
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)
【例013】将列表中排除重复项并将重复的项找出
复制代码 代码如下:
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
复制代码 代码如下:
l = []
l.append(1)
l.append(2)
l.append(3)
print l
print l.pop()
print l.pop()
print l.pop()
【例015】对列表中的单词按首字母排序
复制代码 代码如下:
>>> 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
复制代码 代码如下:
john black
Jerry!
&alice
TOm#
south carolina###
mr smith?
代码及输出结果如下:
复制代码 代码如下:
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
复制代码 代码如下:
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\’
【例018】用while实现搜索某个字符串的功能
复制代码 代码如下:
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
复制代码 代码如下:
>>> T = ((1,2),(3,4),(5,6))
>>> for (a,b) in T:
… print a+100, b+200
…
101 202
103 204
105 206
【例020】用for循环实现查找
复制代码 代码如下:
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
复制代码 代码如下:
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
复制代码 代码如下:
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
复制代码 代码如下:
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
复制代码 代码如下:
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
复制代码 代码如下:
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:
复制代码 代码如下:
>>>
[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
复制代码 代码如下:
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
复制代码 代码如下:
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
复制代码 代码如下:
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
复制代码 代码如下:
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
复制代码 代码如下:
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
复制代码 代码如下:
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
复制代码 代码如下:
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
复制代码 代码如下:
#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
复制代码 代码如下:
\’\’\’\’\’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
复制代码 代码如下:
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)
复制代码 代码如下:
# 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
复制代码 代码如下:
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
复制代码 代码如下:
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
复制代码 代码如下:
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:
复制代码 代码如下:
>>>
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
复制代码 代码如下:
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:
复制代码 代码如下:
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
复制代码 代码如下:
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:
复制代码 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
复制代码 代码如下:
template=\’\’\’\’\'
%(title)s
\’\’\’
data = {\’title\’:\’My Home Page\’,\’text\’:\’Welcome to my home page!\’}
print template % data
#输出结果:
>>>
My Home Page
【例042】需找100以内的最大平方数
复制代码 代码如下:
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
复制代码 代码如下:
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
【例044】将两个列表中首字母相同的提取出来
复制代码 代码如下:
#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
复制代码 代码如下:
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:
复制代码 代码如下:
>>> 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
复制代码 代码如下:
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
复制代码 代码如下:
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!）
复制代码 代码如下:
# -*- 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
复制代码 代码如下:
#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:
复制代码 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\’)