在HeadFirstPython網站中下載所有文件,解壓后以chapter 3中的“sketch.txt”為例:
新建IDLE會話,首先導入os模塊,并將工作目錄卻換到包含文件“sketch.txt”的文件夾,如C://Python33//HeadFirstPython//chapter3
打開文件“sketch.txt”,讀取并顯示前兩行:
回到文件起始位置,使用for語句處理文件中的每行,最后關閉文件:
Man: Is this the right room for an argument?
Other Man: I've told you once.
Man: No you haven't!
Other Man: Yes I have.
Man: When?
Other Man: Just now.
Man: No you didn't!
Other Man: Yes I did!
Man: You didn't!
Other Man: I'm telling you, I did!
Man: You did not!
Other Man: Oh I'm sorry, is this a five minute argument, or the full half hour?
Man: Ah! (taking out his wallet and paying) Just the five minutes.
Other Man: Just the five minutes. Thank you.
Other Man: Anyway, I did.
Man: You most certainly did not!
Other Man: Now let's get one thing quite clear: I most definitely told you!
Man: Oh no you didn't!
Other Man: Oh yes I did!
Man: Oh no you didn't!
Other Man: Oh yes I did!
Man: Oh look, this isn't an argument!
(pause)
Other Man: Yes it is!
Man: No it isn't!
(pause)
Man: It's just contradiction!
Other Man: No it isn't!
Man: It IS!
Other Man: It is NOT!
Man: You just contradicted me!
Other Man: No I didn't!
Man: You DID!
Other Man: No no no!
Man: You did just then!
Other Man: Nonsense!
Man: (exasperated) Oh, this is futile!!
(pause)
Other Man: No it isn't!
Man: Yes it is!
>>> data.close()
讀取文件后,將不同role對應數據分別保存到列表man和other:
try:
data=open("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:
pass
data.close()
except IOError:
print('The datafile is missing!')
print (man)
print (other)
Tips:
使用open()方法打開磁盤文件時,默認的訪問模式為r,表示讀,不需要特意指定;
要打開一個文件完成寫,需要指定模式w,如data=open("sketch.txt","w"),如果該文件已經存在則會清空現有內容;
要追加到一個文件,需要指定模式a,不會清空現有內容;
要打開一個文件完成寫和讀,且不清空現有內容,需要指定模式w+;
例如,將上例中保存的man和other內容以文件方式保存時,可修改如下:
try:
data=open("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:
pass
data.close()
except IOError:
print('The datafile is missing!')
try:
man_file=open('man.txt', 'w') #以w模式訪問文件man.txt
other_file=open('other.txt','w') #以w模式訪問文件other.txt
print (man, file=man_file) #將列表man的內容寫到文件中
print (other, file=other_file)
except IOError:
print ('File error')
finally:
man_file.close()
other_file.close()
但是第26行print()為什么會報錯?“syntax error while detecting tuple”,有大神能給解惑一下不
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