Python打開文件、文件讀寫操作、with方式、文件常用函數(shù)實(shí)例分析

open(file, mode='r', buffering=None, encoding=None, errors=None, newline=None, closefd=True)

file--文件名

mode—打開模式，默認(rèn)只讀模式

buffering--如果buffering的值被設(shè)為0，就不會(huì)有寄存。如果buffering的值取1，訪問文件時(shí)會(huì)寄存行。如果將buffering的值設(shè)為大于1的整數(shù)，表明了這就是的寄存區(qū)的緩沖大小。如果取負(fù)值，寄存區(qū)的緩沖大小則為系統(tǒng)默認(rèn)。

encoding—打開文件的編碼方式 

print("r".center(50,'-'))
f=open("file.txt",encoding="utf-8")
print(f.read())
f.close()
-----------------
運(yùn)行結(jié)果：
my
sas
aaa
fsafsa
中文
中文
葫蘆娃

print("r".center(50,'-'))
f=open("file.txt",encoding="utf-8")
print(f.read())
f.close()
---------------------------
運(yùn)行結(jié)果：
my
sas
aaa
fsafsa
中文
中文
葫蘆娃

print("r".center(50,'-'))
f=open("file.txt",encoding="utf-8")
print(f.readline())
f.close()

-----------
運(yùn)行結(jié)果：
my

print("r".center(50,'-'))
f=open("file.txt",encoding="utf-8")
print(f.readlines())
f.close()




#------------------------r-------------------------
#運(yùn)行結(jié)果：
['my\n', 'sas\n', 'aaa\n', 'fsafsa\n', '中文\n', '中文\n', '葫蘆娃\n', '\n']

print("r".center(50,'-'))
f=open("file.txt","r+",encoding="utf-8")
# print(f.readline())
f.write("hello mike")
f.close()

print("r".center(50,'-'))
f=open("file.txt","r+",encoding="utf-8")
print(f.readline())
f.write("hello mike")
f.close()

myfile=open("myfile1","wb")
myfile.write(b"nnnnnn")
myfile.write("my葫蘆娃".encode("utf-8"))
myfile.close()

myfile=open("myfile1","wb")
myfile.write(b"nnnnnn")

myfile.writelines([b'1',b'2',b'3',b'4'])
myfile.close()

myfile=open("myfile1","wb+")
myfile.write(b"nnnnnn")
myfile.seek(0)
print(myfile.read())
myfile.close()

myfile=open("myfile1","wb+")
myfile.write(b"1nnnnnn")
site=myfile.tell()
myfile.write(b"2nnnnnn")
myfile.seek(site)##讀出后一段
print(myfile.read())
myfile.close()

with open("file.txt","r+",encoding="utf-8") as f:##將自動(dòng)執(zhí)行f.close()
 print(f.tell())
 f.write("金剛")
 for line in f:
  print(line,end="")

with open("file.txt",'r') as f ,\
open("file.new",'r') as m:
 print(f.read(),m.read())

myfile=open("myfile1","wb+")
myfile.write(b"1nnnnnn")
site=myfile.tell()
myfile.write(b"2nnnnnn")
myfile.seek(site)##讀出后一段
print(myfile.read())
myfile.close()

import time
myfile=open("myfile1","wb+")
myfile.write(b"1nnnnnn")
time.sleep(10)
# myfile.flush()
myfile.write(b"2nnnnnn")
myfile.close()

import time
myfile=open("myfile1","wb+")
myfile.write(b"1nnnnnn")
myfile.flush()
time.sleep(10)
myfile.write(b"2nnnnnn")
myfile.close()

print("r".center(50,'-'))
f=open("file.txt","r+",encoding="utf-8")

print(f.readline())
print("----truncate()-------")
print(f.tell())
m=f.tell()
f.truncate(m)#內(nèi)容從0位置截?cái)嗟街付ㄎ恢?，不論?dāng)前光標(biāo)位置
f.close()