Python os.truncate()

Python os.truncate()方法截断与path对应的文件，使其大小不超过长度字节。这个函数也可以支持文件描述符。

语法:os.truncate(path, length)

参数:

path:该参数是要被截断文件的路径或文件描述符。

length:这是要截断的文件的长度。

返回值:此方法不返回任何值。

示例1

使用os.truncate()方法使用文件的路径截断文件。

# Python program to explain os.truncate() method 
        
# importing os module 
import os 
    
# path 
path = 'C:/Users/Rajnish/Desktop/testfile.txt'
  
# Open the file and get
# the file descriptor associated
# with it using os.open() method
fd = os.open(path, os.O_RDWR|os.O_CREAT)
  
# String to be written
s = 'GeeksforGeeks - A Computer Science portal'
  
# Convert the string to bytes 
line = str.encode(s)
  
# Write the bytestring to the file 
# associated with the file 
# descriptor fd 
os.write(fd, line)
  
# Using os.truncate() method
# Using path as parameter
os.truncate(path, 10)
  
# Seek the file from beginning
# using os.lseek() method
os.lseek(fd, 0, 0)
  
# Read the file
s = os.read(fd, 15)
  
# Print string
print(s)
  
# Close the file descriptor 
os.close(fd)

输出:

b'GeeksforGe'

示例2

使用os.truncate()方法使用文件描述符截断文件

# Python program to explain os.truncate() method 
        
# importing os module 
import os 
    
# path 
path = 'C:/Users/Rajnish/Desktop/testfile.txt'
  
# Open the file and get
# the file descriptor associated
# with it using os.open() method
fd = os.open(path, os.O_RDWR|os.O_CREAT)
  
# String to be written
s = 'GeeksforGeeks'
  
# Convert the string to bytes 
line = str.encode(s)
  
# Write the bytestring to the file 
# associated with the file 
# descriptor fd 
os.write(fd, line)
  
# Using os.truncate() method
# Using fd as parameter
os.truncate(fd, 4)
  
# Seek the file from beginning
# using os.lseek() method
os.lseek(fd, 0, 0)
  
# Read the file
s = os.read(fd, 15)
  
# Print string
print(s)
  
# Close the file descriptor 
os.close(fd)