os.path.getsize报告最后带有L的文件大小,为什么？

Question

import os, sys

def crawlLocalDirectories(directoryToCrawl):
    crawledDirectory = [os.path.join(path, subname) for path, dirnames, filenames in os.walk(directoryToCrawl) for subname in dirnames + filenames]
    return crawledDirectory

print crawlLocalDirectories('.')

dictionarySize = {}
def getSizeOfFiles(filesToMeasure):
    for everyFile in filesToMeasure:
        size = os.path.getsize(everyFile)
        dictionarySize[everyFile] = size
    return dictionarySize

print getSizeOfFiles(crawlLocalDirectories('.'))

无论何时运行,我得到输出{'example.py':392L},为什么？什么是L？我不想在最后剥掉L.

如果我在没有将其添加到字典的情况下运行它,它将返回文件大小为392.

Answer 1

这仅显示或以交互模式显示,或者通过时获得字符串表示repr().正如zigg所写,你可以简单地忽略它.考虑这个实现细节.在正常的int和long int之间做出区分很重要的时候,它可能很有用.例如,在Python 3中没有L.无论多大,int都是int:

d:\>py
Python 3.2.1 (default, Jul 10 2011, 20:02:51) [MSC v.1500 64 bit (AMD64)] on win
32
Type "help", "copyright", "credits" or "license" for more information.
>>> a = 100000000000000000000000000000000000000000000
>>> a
100000000000000000000000000000000000000000000
>>> ^Z

d:\>python
Python 2.7.3 (default, Apr 10 2012, 23:24:47) [MSC v.1500 64 bit (AMD64)] on win
32
Type "help", "copyright", "credits" or "license" for more information.
>>> a = 100000000000000000000000000000000000000000000
>>> a
100000000000000000000000000000000000000000000L
>>>

请注意LPython 2.7,但Python 3.2没有类似的东西.

Answer 2

尾随L意味着你有一个long.实际上,你总是有,但print荷兰国际集团一dict将显示值的可打印表示,包括L符号; 但是,打印long本身只显示数字.

你几乎肯定不用担心剥离尾随L; 您可以像long在使用时一样在所有计算中使用int.