indata = open(from_file).read() 这种写法 open 得到的 file object 是执行完这一句就释放了还是脚本结束释放的？

[laoyuan]

既然 open(from_file) 得到的 file object 没有保存到任何变量，已经没法再使用了，是不是执行完这一行就释放了呢？如果不是的话，这样写可不可以手动关闭呢：

from_file = 'sample.txt'
indata = open(from_file).read()
open(from_file).close()

[Septembers]

https://gist.github.com/anonymous/1cc2fa5fcec81d559739
标准姿势

[oclock]

read()执行完就被gc，因为*open(from_file)*没有被引用
喜欢oneliner可以那么写

[laoyuan]

@oclock 我感觉没有立刻回收呢，下面这三行print 地址都是相同的

from_file = 'sample.txt'
print open(from_file)
print open(from_file)
indata = open(from_file).read()
print open(from_file)

[Sylv]

"Close is always necessary when dealing with files, it is not a good idea to leave open file handles all over the place. They will eventually be closed when the file object is garbage collected but you do not know when that will be and in the mean time you will be wasting system resources by holding to file handles you no longer need."

[laoyuan]

@Sylv 是啊，所以才有脑洞大开的 open(from_file).close() 这种写法

[ryanking8215]

@oclock gc是释放垃圾内存，不是资源，你这样还占着一个文件描述符。
@Septembers 正解姿势，我喜欢。

[czy1996]

@ryanking8215 请教一下，还是不太明白，笨办法学python里说这样写的话read()一旦运行就被关掉了。