Python文件處理
文件內容替換
for line infileinput.input(“filepath”,inplace=1):
line=line.replace(“oldtest”,”newtest”)
print line,
//包含oldtest的替換成newtest
例子：
wangchao@wangchao-virtual-machine:~/python$vim finput.py
#!/usr/bin/env python
import fileinput
for line infileinput.input("contact_list.txt",backup='bak',inplace=1):
line = line.replace('wang','chao')
print line,
//將文件中wang改成chao,並將原文件備份一份bak文件
程序運行結果
wangchao@wangchao-virtual-machine:~/python$python finput.py
wangchao@wangchao-virtual-machine:~/python$ls
contact_list.txtbak
修改某行
with open(“foo.txt”,”r+”) as f:
old=f.read()#read everything in the file
f.seek()#rewind
f.write(“new line\n”+old)#write the new
line before
例子：
wangchao@wangchao-virtual-machine:~/python$vim fseek.py
#f = open('contact_list.txt','r+')
withopen('contact_list.txt',"r+") as f :
old = f.read()
f.seek(14)
f.write("new line\n")
//f.seek(14),文件從第14個字符開始加newline,並換行
程序運行結果
wangchao@wangchao-virtual-machine:~/python$more contact_list.txt
1 cai chengxnew 1885
2 ru gongchengshi 1886
3 chao gongchengshi 1887
4 yao chengxuyuan 1888
wangchao@wangchao-virtual-machine:~/python$python fseek.py
wangchao@wangchao-virtual-machine:~/python$more contact_list.txt
1 cai chengxnew line
85
2 ru gongchengshi 1886
3 chao gongchengshi 1887
4 yao chengxuyuan 1888
wangchao@wangchao-virtual-machine:~$ vimtest.txt
wangchao@wangchao-virtual-machine:~/python$python
>>> f=file('test.txt') //打開只讀模式
>>> f=file('test.txt','w') //打開可寫
>>> f.write('hello world!') //寫入
>>> f.flush() //文件新建或被保存
>>> f.close()
>>> f=file('test.txt','a')
>>> f.write('AAA') //追加內存
wangchao@wangchao-virtual-machine:~/python$cat test.txt
hello world!AAA
python列表
處理和存放一組數據
用途：購物列表、工資列表……
語法：ShoppingList =[‘car’,’clothes’,’iphone’]
添加book到ShoppingList列表：shoppingList.append(‘book’)
刪除car: ShoppingList.remove(‘car’)
刪除最後一個： ShoppingList.pop()
刪除列表中第二個內容：ShoppingList.pop(1)
wangchao@wangchao-virtual-machine:~/python$python
>>>nameList=['wang','cai','ru','yao']
>>> nameList
['wang', 'cai', 'ru', 'yao']
>>> nameList[2] //取出2號，從0開始數
'ru'
>>> nameList[-1] //取出最後一個
'yao'
>>> nameList.append('fei') //加入fei
>>> nameList
['wang', 'cai', 'ru', 'yao', 'fei']
>>> nameList.insert(2,'sun') //在2號前插入sun
>>> nameList
['wang', 'cai', 'sun', 'ru', 'yao', 'fei']
>>> nameList.count('wang') //統計wang出現的個數
1
>>> 'cai' in nameList //判斷cai是否在列表中
True
>>> nameList
['wang', 'cai', 'sun', 'ru', 'yao', 'fei']
>>> nameList.index('fei') //索引，fei在列表中的位置
5
>>> nameList.pop() //刪除最後一個
'fei'
>>> nameList
['wang', 'cai', 'sun', 'ru', 'yao']
>>> nameList.remove('Y') //刪除一個元素Y，如果其中有兩個Y，將只刪除前面一個
>>> nameList.reverse() //排序
>>> nameList
['yao', 'ru', 'sun', 'cai', 'wang']
>>> nameList.reverse() //排回
>>> nameList
['wang', 'cai', 'sun', 'ru', 'yao']
>>> nameList.sort() //按字母排序
>>> nameList
['cai', 'ru', 'sun', 'wang', 'yao']
>>> nameList.extend('hello world')
>>> nameList
['cai', 'ru', 'sun', 'wang', 'yao', 'h','e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd']
>>> nameList[1]='ruru' //修改1號爲ruru
>>> nameList
['cai', 'ruru', 'sun', 'wang', 'yao', 'h','e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd']
>>> nameList.index('h') //查找h所在的位置
5
>>> i=nameList.index('h')
>>> nameList[i]='H' //將h改成H
>>> nameList
['cai', 'ruru', 'sun', 'wang', 'yao', 'H','e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd']
元組
與列表一樣，但內容一旦生成，不可修改
NameList=(‘cai’,’ru’,’wang’)
遍歷列表
NameList=[‘cai’,’ru’,’wang’]
for name in NameList
Print‘your name is’,name
列表練習程序
讓用戶輸入工資
輸出購物菜單及產品價格
計算用戶是否可支付
輸出用戶剩餘的錢，問用戶是否可繼續購物，如果選擇繼續，繼續進行，直到錢不夠爲止
補充：
>>> names="cai ru wang" //定義一變量爲字符串
>>> names.split() //將字符串分成一個列表
['cai', 'ru', 'wang']
>>> name_list=names.split()
>>> name_list //字符串被分成三段
['cai', 'ru', 'wang']
>>> name_list[1] //取出ru
'ru'
F_choice=choice.strip() //使choice脫去空格（多餘的）
參考程序：
wangchao@wangchao-virtual-machine:~/python$vim mai.py
#!/usr/bin/python
import tab
import sys
products = ['Car','Iphone','Coffee','Mac','Cloths','Bicyle']
prices = [250000,4999, 35, 9688, 438, 1500]
shop_list=[]
salary = int(raw_input('please input yoursalary:'))
while True:
print "Things have in the shop.plesae choose one to buy:"
for p in products:
print p,'\t',prices[products.index(p)]
choice = raw_input('Please input one item to buy:')
F_choice = choice.strip()
if F_choice in products:
product_price_index = products.index(F_choice)
product_price = prices[product_price_index]
print F_choice,product_price
if salary > product_price:
shop_list.append(F_choice)
print "Added %s intoyour shop list" % F_choice
salary = salary -product_price
print "Salaryleft:",salary
else:
if salary < min(prices):
print 'Sorry,rest ofyour salary cannot buy anything! 88'
print "you havebought these things: %s" % shop_list
sys.exit()
else:
print "Sorry ,youcannot afford this product,please try other ones!"
程序運行結果：
wangchao@wangchao-virtual-machine:~/python$python mai.py
please input your salary:1536
Things have in the shop.plesae choose oneto buy:
Car 250000
Iphone 4999
Coffee 35
Mac 9688
Cloths 438
Bicyle 1500
Please input one item to buy:Car
Car 250000
Sorry ,you cannot afford thisproduct,please try other ones!
Things have in the shop.plesae choose oneto buy:
Car 250000
Iphone 4999
Coffee 35
Mac 9688
Cloths 438
Bicyle 1500
Please input one item to buy:Bicyle
Bicyle 1500
Added Bicyle into your shop list
Salary left: 36
Things have in the shop.plesae choose oneto buy:
Car 250000
Iphone 4999
Coffee 35
Mac 9688
Cloths 438
Bicyle 1500
Please input one item to buy:Bicyle
Bicyle 1500
Sorry ,you cannot afford thisproduct,please try other ones!
Things have in the shop.plesae choose oneto buy:
Car 250000
Iphone 4999
Coffee 35
Mac 9688
Cloths 438
Bicyle 1500
Please input one item to buy:Coffee
Coffee 35
Added Coffee into your shop list
Salary left: 1
Things have in the shop.plesae choose oneto buy:
Car 250000
Iphone 4999
Coffee 35
Mac 9688
Cloths 438
Bicyle 1500
Please input one item to buy:Coffee
Coffee 35
Sorry,rest of your salary cannot buyanything! 88
you have bought these things: ['Bicyle','Coffee']
wangchao@wangchao-virtual-machine:~/python$
Python字典講解與練習
python字典
語法：
DicName={
“key1”: “value”,
“key2”: “value 2”
Contacs={
‘wang’: ‘1886’,
‘cai’: ‘1887’,
‘ru’: ‘1888’,
}
將之前寫的購物菜單用字典寫：
>>> product_dir={'car':250000,'Iphone':4999,'coffee':35,'Bicycle':1500}
>>> product_dir //查看菜單
{'car': 250000, 'coffee': 35, 'Bicycle':1500, 'Iphone': 4999}
>>> product_dir['coffee'] //查價格
35
>>> product_dir.keys() //查key
['car', 'coffee', 'Bicycle', 'Iphone']
>>> product_dir.values() //查values
[250000, 35, 1500, 4999]
>>> product_dir.items() //查相對應的
[('car', 250000), ('coffee', 35),('Bicycle', 1500), ('Iphone', 4999)]
>>> for i in product_dir: //打印product_dir
... print i
...
car
coffee
Bicycle
Iphone
>>> product_dir.items()
[('car', 250000), ('coffee', 35),('Bicycle', 1500), ('Iphone', 4999)]
>>> for p,price in product_dir.items(): //打印items()
... print p,price
...
car 250000
coffee 35
Bicycle 1500
Iphone 4999
字典查看、添加、刪除、修改
語法：
Contacs={
‘wang’:’1886’,
‘cai’:’1887’;
‘ru’:’1888’}
查看key: Contacts.key()
查看value: Contacts.values()
添加新item到字典： Contacts[‘yao’]=’1889’
刪除item: Contacts.popitem() //默認刪除第一個
>>> product_dir
{'car': 250000, 'coffee': 35, 'Bicycle':1500, 'Iphone': 4999}
>>>product_dir.has_key('car') //判斷car是否存在
True
>>> product_dir.popitem() //刪除第一個
('car', 250000)
>>> product_dir
{'coffee': 35, 'Bicycle': 1500, 'Iphone':4999}
練習小程序：員工信息表
1.創建公司員工信息表，員工號、姓名、職位、手機
2.提供查找接口，通過員工姓名查詢用戶信息
參考程序：
wangchao@wangchao-virtual-machine:~/python$cat contact_list.txt
1 cai chengxuyuan 1885
2 ru gongchengshi 1886
3 chao gongchengshi 1887
4 yao chengxuyuan 1888
wangchao@wangchao-virtual-machine:~/python$vim contact_dir.py
#!/usr/bin/python
import tab
contact_file = 'contact_list.txt'
f = file(contact_file)
contact_dic = {}
for line in f.readlines():
name = line.split()[1]
contact_dic[name] = line
'''
for n,v in contact_dic.items():
print "%s \t%s" %(n,v),
'''
while True:
input = raw_input("Please input the staff name:").strip()
if len(input) == 0:continue
if contact_dic.has_key(input):
print "\033[32.1m%s\033[0m" % contact_dic[input]
else:
print 'Sorry,no staff namefound!'
程序運行結果：
wangchao@wangchao-virtual-machine:~/python$python contact_dir.py
Please input the staff name:zhou
Sorry,no staff name found!
Please input the staff name:cai
1 cai chengxuyuan 1885
Please input the staff name:chao
3 chao gongchengshi 1887
Please input the staff name:yao
4 yao chengxuyuan 1888
Please input the staff name:ru
2 ru gongchengshi 1886
Please input the staff name:
Python函數
函數是在程序中將一組用特定的格式包裝起，定義一個名稱，然後可以在程序的任何地方通過調用此函數名來執行函數裏的那組命令
使用函數的好處：
程序可擴展性
減少程序代碼
方便程序架構的更改
定義函數
def sayHi():
print“hello,world!”
def sayHi2(name):
print“hello,%s,howare you?” %name
n=’wang’
sayHi2(n)
>>>sayHi(n)
Hello,wang,how are you?
小試牛刀1:
wangchao@wangchao-virtual-machine:~/python$vim function1.py
#!/usr/bin/env python
def sayHi(n):
print "Hello %s,how are you?" % n
name = 'wang'
sayHi(name)
wangchao@wangchao-virtual-machine:~/python$python function1.py
Hello wang,how are you?
小試牛刀2:
wangchao@wangchao-virtual-machine:~/python$more contact_list.txt
1 cai chengxuyuan 1885
2 ru gongchengshi 1886
3 chao gongchengshi 1887
4 yao chengxuyuan 1888
將名字取出，一個一個問hello XXX,how are you
參考：
wangchao@wangchao-virtual-machine:~/python$vim function2.py
#!/usr/bin/python
def sayHi(n):
print "hello %s,how are you?" %n
contact_file ='contact_list.txt'
f = file(contact_file)
for line in f.readlines():
name = line.split()[1]
sayHi(name)
程序結果：
wangchao@wangchao-virtual-machine:~/python$python function2.py
hello cai,how are you?
hello ru,how are you?
hello chao,how are you?
hello yao,how are you?
函數參數
def info(name,age):
print“Name:%s Age:%s” %(name,age)
綜合練習：
寫一個atm程序，功能要求：
額度15000
可以提現，手續費5%
每月最後一天出賬單（每月30天）
記錄每月日常消費流水
提供還款接口
優化（可選）：
1．每月10號爲還款日，過期未還，按欠款額5%計息
輸出類似：
本期還款總額: XX
交易日 交易摘要 交易金額 計息
XX XX XX XX
補充：Pickle()#、函數默認參數、關鍵參數可學習一下，寫程序可更加便捷