文件

获取文件最后更新时间

import os

def getUpdateTime(curFileOrPath):
    """get file/folder latest update time = modify time

    Args:
        curFileOrPath (str): some file or folder path
    Returns:
        int: time stamp int of 13 digit, with milliseconds
    Raises:
    """
    updateTime = None
    try:
        modifyTime = os.path.getmtime(curFileOrPath) # 1593748641.3270357
        updateTime = int(modifyTime * 1000) # 1593748641327
    except OSError as err:
        errMsg = str(err)
        # print("errMsg=%s" % errMsg)
        pass

    return updateTime

详见：

【已解决】Python中获取文件最后更新时间

提取文件名后缀

def extractSuffix(fileNameOrUrl):
    """
    extract file suffix from name or url
    eg:
https://cdn2.qupeiyin.cn/2018-09-10/15365514898246.mp4 -> mp4
        15365514894833.srt -> srt
    """
    return fileNameOrUrl.split('.')[-1]

创建空文件

import os

def createEmptyFile(fullFilename):
    """Create a empty file like touch"""
    filePath = os.path.dirname(fullFilename)
    # create folder if not exist
    if not os.path.exists(filePath):
        os.makedirs(filePath)

    with open(fullFilename, 'a'):
        # Note: not use 'w' for maybe conflict for others constantly writing to it
        os.utime(fullFilename, None)

读取文件二进制数据

def readBinDataFromFile(fileToRead):
    """Read binary data from file"""
    binaryData = None
    try:
        readFp = open(fileToRead, "rb")
        binaryData = readFp.read()
        readFp.close()
    except:
        binaryData = None


    return binaryData

调用：

imgBinData = readBinDataFromFile(imageFullPath)

保存二进制数据到文件

def saveDataToFile(fullFilename, binaryData):
    """save binary data info file"""
    with open(fullFilename, 'wb') as fp:
        fp.write(binaryData)
        fp.close()
        # print("Complete save file %s" % fullFilename)

保存json到文件

import json
import codecs

def saveJsonToFile(fullFilename, jsonValue):
    """save json dict into file"""
    with codecs.open(fullFilename, 'w', encoding="utf-8") as jsonFp:
        json.dump(jsonValue, jsonFp, indent=2, ensure_ascii=False)
        # print("Complete save json %s" % fullFilename)

从文件中加载出json

import json
import codecs

def loadJsonFromFile(fullFilename):
    """load and parse json dict from file"""
    with codecs.open(fullFilename, 'r', encoding="utf-8") as jsonFp:
        jsonDict = json.load(jsonFp)
        # print("Complete load json from %s" % fullFilename)
        return jsonDict

通过二进制生成文件类型对象

（1）Python 3

import io

audioBinaryData = audioObj.read()
audioFileLikeObj = io.BytesIO(audioBinaryData)

得到对应的文件类型的对象的：<_io.BytesIO object at 0x115964468>，即可去像操作文件一样去操作这个io。

（2）Python 2

import StringIO

audioFileLikeObj = StringIO.StringIO()
audioFileLikeObj.write(audioBinaryData)

一行代码把字符串写入保存到文件

open(fullFilePath, "w").write(fileContentStr).close()

举例：

open("0408_1600.xml", "w").write(page).close()

给文件增加可执行权限：实现chmod +x的效果

代码：

import os
import stat

curState = os.stat(someFile)
newState = curState.st_mode | stat.S_IEXEC
os.chmod(someFile, newState)

再去优化为函数：

import os
import stat

def chmodAddX(someFile):
    """add file executable mode, like chmod +x

    Args:
        someFile (str): file full path
    Returns:
        soup
    Raises:
    """
    if os.path.exists(someFile):
        if os.path.isfile(someFile):
            # add executable
            curState = os.stat(someFile)
            newState = curState.st_mode | stat.S_IEXEC
            os.chmod(someFile, newState)

调用：

chmodAddX(shellFullPath)

继续优化：

参考 How do you do a simple "chmod +x" from within python? - Stack Overflow

如果想要加上，给任何人都有可执行权限，则可以用：

def chmodAddX(someFile):
    """add file executable mode, like chmod +x

    Args:
        someFile (str): file full path
    Returns:
        soup
    Raises:
    """
    if os.path.exists(someFile):
        if os.path.isfile(someFile):
            # add executable
            curState = os.stat(someFile)
            # STAT_OWNER_EXECUTABLE = stat.S_IEXEC
            # executableMode = STAT_OWNER_EXECUTABLE
            STAT_EVERYONE_EXECUTABLE = stat.S_IXUSR | stat.S_IXGRP | stat.S_IXOTH
            executableMode = STAT_EVERYONE_EXECUTABLE
            newState = curState.st_mode | executableMode
            os.chmod(someFile, newState)

效果：

• 之前：-rw-r--r--
• 之后：-rwxr-xr-x
  • 给 user group other 都加上x的可执行权限

详见：

【已解决】Python中给Mac中文件加上可执行权限

判断是否是文件对象

import sys

def isFileObject(fileObj):
    """"check is file like object or not"""
    if sys.version_info[0] == 2:
        return isinstance(fileObj, file)
    else:
        # for python 3:
        # has read() method for:
        # io.IOBase
        # io.BytesIO
        # io.StringIO
        # io.RawIOBase
        return hasattr(fileObj, 'read')

计算当前文件名，如果重名，则位数加1

import os
import re

def findNextNumberFilename(curFilename):
    """Find the next available filename from current name

    Args:
        curFilename (str): current filename
    Returns:
        next available (not existed) filename
    Raises:
    Examples:
        (1) 'crifanLib/demo/input/image/20201219_172616_drawRect_40x40.jpg'
            not exist -> 'crifanLib/demo/input/image/20201219_172616_drawRect_40x40.jpg'
        (2) 'crifanLib/demo/input/image/20191219_172616_drawRect_40x40.jpg'
            exsit -> next until not exist 'crifanLib/demo/input/image/20191219_172616_drawRect_40x40_3.jpg'
    """
    newFilename = curFilename

    newPathRootPart, pointSuffix = os.path.splitext(newFilename)
    # 'crifanLib/demo/input/image/20191219_172616_drawRect_40x40_1'
    filenamePrefix = newPathRootPart
    while os.path.exists(newFilename):
        newTailNumberInt = 1
        foundTailNumber = re.search("^(?P<filenamePrefix>.+)_(?P<tailNumber>\d+)$", newPathRootPart)
        if foundTailNumber:
            tailNumberStr = foundTailNumber.group("tailNumber") # '1'
            tailNumberInt = int(tailNumberStr)
            newTailNumberInt = tailNumberInt + 1 # 2
            filenamePrefix = foundTailNumber.group("filenamePrefix") # 'crifanLib/demo/input/image/20191219_172616_drawRect_40x40'
        # existed previously saved, change to new name
        newPathRootPart = "%s_%s" % (filenamePrefix, newTailNumberInt)
        # 'crifanLib/demo/input/image/20191219_172616_drawRect_40x40_2'
        newFilename = newPathRootPart + pointSuffix
        # 'crifanLib/demo/input/image/20191219_172616_drawRect_40x40_2.jpg'

    return newFilename

调用：

  notExistFile = "crifanLib/demo/input/image/some_not_exist_filename.jpg"
  nextFilename = findNextNumberFilename(notExistFile)
  print("notExistFile=%s -> nextFilename=%s" % (notExistFile, nextFilename))
  # notExistFile=crifanLib/demo/input/image/some_not_exist_filename.jpg -> nextFilename=crifanLib/demo/input/image/some_not_exist_filename.jpg

  realExistFile = "crifanLib/demo/input/image/20191219_172616_drawRect_40x40.jpg"
  nextUntilNotExistFilename = findNextNumberFilename(realExistFile)
  print("realExistFile=%s -> nextUntilNotExistFilename=%s" % (realExistFile, nextUntilNotExistFilename))
  # realExistFile=crifanLib/demo/input/image/20191219_172616_drawRect_40x40.jpg -> nextUntilNotExistFilename=crifanLib/demo/input/image/20191219_172616_drawRect_40x40_2.jpg

从文件名后缀推断出MIME类型

用库：

• mime
  • GitHub
    • https://github.com/liluo/mime

安装mime：

pip install mime

代码：

import mime

fileMimeType = mime.Types.of(curAudioFullFilename)[0].content_type

• 输入文件：'Lots of Hearts.mp3'
• 输出信息：'audio/mpeg'