Head First Python-Python中与文件相关的操作-读、处理、写
最近在看head first python,前面也寫(xiě)了一些筆記,但是基本上沒(méi)有涉及到一些完整的代碼,現(xiàn)在將書(shū)中的文件相關(guān)操作的代碼整理,供以后參考。
主要分為兩大部分,讀取文件、處理異常,處理文件、存儲(chǔ)文件。
0,處理文件
首先介紹后面將會(huì)用到的知識(shí)點(diǎn),格式化輸出列表;
如果一個(gè)列表嵌套多層列表,使用一般的方法來(lái)打印無(wú)法打印出嵌套的列表。下面的方法只能打印出一層,如果想打印多層怎么辦?
movies=['aWith a ','bpopulation of 1060', ['cthe village','dis carpeted with ','eazalea blossoms', ['fwith fast-flowing rivers ','gscattered guesthouses','hadding strokes and splashes to ','ithe natural canvas.']]]print(movies) def printList(movies):for i in movies:print(i) print(printList(movies))下面通過(guò)給printList增加參數(shù)來(lái)控制格式化輸出(intent控制是否需要格式化,t用來(lái)控制指標(biāo)表符個(gè)數(shù)):
movies=['aWith a ','bpopulation of 1060', ['cthe village','dis carpeted with ','eazalea blossoms', ['fwith fast-flowing rivers ','gscattered guesthouses','hadding strokes and splashes to ','ithe natural canvas.']]]print(movies)#1def printList(movies,intent=False,t=0):for i in movies:if isinstance(i , list): #isinstance檢查一個(gè)標(biāo)識(shí)符是否指示某個(gè)指定類(lèi)型的數(shù)據(jù)對(duì)象# for j in i:printList(i,intent,t+1)#增加一層嵌套制表符加1else:if intent:for j in range(t):print("\t", end='')print(i)print(printList(movies,False))#2 print(printList(movies,True,0))#3輸出如下:
?
?1,讀取文件
pyhont中使用open來(lái)打開(kāi)一個(gè)文件:
import os if os.path.exists('./temp/sketch.txt'):data =open('./temp/sketch.txt')print(data.readline(),end='')print(data.readline(),end='')data.seek(0)for each_line in data:if not each_line.find(':') == -1:(role,line_spoken)=each_line.split(':',1)print(role,end='')print(' said: ',end='')print(line_spoken,end='')data.close() else:print('file not exists!!!')2,處理異常
如果要讀取的文件不存在咋辦?
data =open('./temp/sketch.txt') print(data.readline(),end='') print(data.readline(),end='') data.seek(0) for each_line in data:try:(role,line_spoken)=each_line.split(':',1)print(role,end='')print(' said: ',end='')print(line_spoken,end='')except ValueError:pass data.close()我們知道,打開(kāi)一個(gè)文件,讀取或者寫(xiě)入結(jié)束后要進(jìn)行關(guān)閉。
3,存儲(chǔ)文件
保存一個(gè)文件:
(1)使用print(),print函數(shù)的參數(shù)file來(lái)定義輸出對(duì)象,默認(rèn)輸出到屏幕:
man = [] other = [] try:data=open('./data/sketch.txt')for each_line in data:try:(role,line_spoken)=each_line.split(':',1)line_spoken=line_spoken.strip()if role=='Man':man.append(line_spoken)elif role=='Other Man':other.append(line_spoken)except ValueError:passdata.close() except IOError as err:print("the datafile is missing..."+str(err))try:with open('./temp/man_data.txt','a') as man_data:print(man, file=man_data)with open('./temp/other_data.txt','a') as other_data:print(other, file=other_data) except IOError as err:print ('ERROR: '+str(err))(2)使用pickle(),pickle函數(shù)有存文件dump()和讀文件load()兩個(gè)方法,將文件以二進(jìn)制流的形式存儲(chǔ)到本地:
import pickle import sysdef print_lol(the_list,indent=False,level=0,lol=sys.stdout):for each_item in the_list:if isinstance(each_item,list):print_lol(each_item,indent,level+1,lol)else:if indent:for tab_stop in range(level):print('\t',end='',file=lol)print(each_item,file=lol)man = [] other = [] try:data=open('./data/sketch.txt')for each_line in data:try:(role,line_spoken)=each_line.split(':',1)line_spoken=line_spoken.strip()if role=='Man':man.append(line_spoken)elif role=='Other Man':other.append(line_spoken)except ValueError:passdata.close() except IOError as err:print("the datafile is missing..."+str(err)) #存文件 try:with open('./temp/man_data.dat','wb') as man_data:pickle.dump(man,man_data)with open('./temp/other_data.dat','wb') as other_data:pickle.dump(other,other_data) except pickle.PickleError as err:print ('ERROR: '+str(err)) #讀文件 new_man=[] try:with open('./temp/man_data.dat','rb') as new_man_file:new_man=pickle.load(new_man_file) except IOError as err:print('IOError: '+str(err)) except pickle.PickleError as perr:print('PickError: '+ str(perr))print_lol(new_man) print(new_man[0]) print(new_man[-1])代碼來(lái)源:head first python
轉(zhuǎn)載于:https://www.cnblogs.com/hoaprox/p/9568935.html
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