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Python3 os.ftruncate () method

Python3 OS file / directory methods Python3 OS file / directory methods


Outline

os.ftruncate () file descriptor fd corresponding crop, it can not exceed the maximum file size.

Available on Unix.

grammar

ftruncate () method syntax is as follows:

os.ftruncate(fd, length)¶

parameter

  • fd - the file descriptor.

  • length - the size of the file you want to crop.

return value

This method has no return value.

Examples

The following example demonstrates ftruncate () method of use:

#!/usr/bin/python3

import os, sys

# 打开文件
fd = os.open( "foo.txt", os.O_RDWR|os.O_CREAT )

# 写入字符串
os.write(fd, "This is test - This is test")

# 使用 ftruncate() 方法
os.ftruncate(fd, 10)

# 读取内容
os.lseek(fd, 0, 0)
str = os.read(fd, 100)
print ("读取的字符串是 : ", str)

# 关闭文件
os.close( fd)

print ("关闭文件成功!!")

The above program output is:

读取的字符串是 :  This is te
关闭文件成功!!

Python3 OS file / directory methods Python3 OS file / directory methods