python学习之路 四 ：文件处理

# 一次性读取文件
f = open("test.txt",‘r‘,encoding=‘gbk‘)
data = f.read()
print(data)
f.close()

# 按行读取
f = open("test.txt",‘r‘,encoding=‘gbk‘)
data = f.readline()
print(data,end=‘‘)
f.close()

# 循环读取
f = open("test.txt",‘r‘,encoding=‘gbk‘)
for line in f:
    print(line,end=‘‘)
f.close()

# 二进制读取
f = open("test.txt",‘rb‘)
data = f.read()
print(data.decode(‘gbk‘))
f.close()

# 按字节读取
f = open("test.txt",‘r‘,encoding=‘gbk‘)
data = f.read(1)
print(data)
f.close()

f = open("test.txt",‘r‘,encoding=‘gbk‘)
data = f.readline(2)
print(data)
f.close()

# 清空原内容写入
f = open(‘test.txt‘,‘w‘,encoding=‘gbk‘)
f.wirte(‘新内容，新世界‘)
f.close()   # 关闭并保存

# 清空原内容写入
f = open(‘test.txt‘,‘a‘,encoding=‘gbk‘)
f.wirte(‘新内容，新世界‘)
f.close()   # 关闭并保存

# 清空原内容写入
f = open(‘test.txt‘,‘wb‘)
f.wirte(‘新内容，新世界‘.encode(‘gbk‘))
f.close()   # 关闭并保存

# flush强刷保存内容
f = open(‘test2.txt‘,‘w‘,encoding=‘gbk‘)
f.write(‘新内容，新世界3‘)
f.flush()  #保存内容

#f.close()

# 一次性修改
f = open("test.txt",‘r+‘,encoding=‘gbk‘)
data = f.read()
f.seek(0)
f.truncate()
data = data.replace(‘Zi‘,‘子‘)
f.write(data)
f.close()

# 边读边改
import os
f_name = "test.txt"
f_temp_name = "test_temp.txt"
f = open(f_name,‘r‘,encoding=‘gbk‘)
f_temp = open(f_temp_name,‘w‘,encoding=‘gbk‘)
for line in f:
    f_temp.write(line.replace(‘子‘,‘Zi‘))
f.close()
f_temp.close()
os.replace(f_temp_name,f_name)