使用:

import os

# For testing purposes the arguments defaulted to the current folder and file.
# returns True if file found
def file_exists(FOLDER_PATH='../', FILE_NAME=__file__):
    return os.path.isdir(FOLDER_PATH) \
        and os.path.isfile(os.path.join(FOLDER_PATH, FILE_NAME))

它基本上是一个文件夹检查,然后使用 os.path.join 使用适当的目录分离器进行文件检查。

添加一个更轻微的变化,这在其他答案中不完全反映。

这将处理文件_路径是无或空的字符串的情况。

此分類上一篇

def file_exists(file_path):
    if not file_path:
        return False
    elif not os.path.isfile(file_path):
        return False
    else:
        return True

添加基于Shahbaz的建议的变量

def file_exists(file_path):
    if not file_path:
        return False
    else:
        return os.path.isfile(file_path)

添加基于Peter Wood的建议的变量

def file_exists(file_path):
    return file_path and os.path.isfile(file_path):

if os.path.isfile(path_to_file):
    try:
        open(path_to_file)
            pass
    except IOError as e:
        print "Unable to open file"

提取例外被认为是一个可接受的,和 Pythonic,方法的流量控制在您的程序. 考虑处理错误的文件与 IOErrors. 在这种情况下,一个 IOError 例外将被提取,如果文件存在,但用户没有阅读许可。

来源:使用Python:如何检查是否存在文件

要检查是否存在文件,

from sys import argv

from os.path import exists
script, filename = argv
target = open(filename)
print "file exists: %r" % exists(filename)

你可以尝试一下(更安全):

try:
    # http://effbot.org/zone/python-with-statement.htm
    # 'with' is safer to open a file
    with open('whatever.txt') as fh:
        # Do something with 'fh'
except IOError as e:
    print("({})".format(e))

奥普特将是:

(没有此类文件或目录:‘whatever.txt’)

然后,取决于结果,你的程序可以只是从那里继续运行,或者你可以编码阻止它,如果你愿意。

这就是我如何在一个文件夹中找到一个文件列表(在这些图像中)并在一个文件夹中搜索它(与子文件夹):

# This script concatenates JavaScript files into a unified JavaScript file to reduce server round-trips

import os
import string
import math
import ntpath
import sys

#import pyodbc

import gzip
import shutil

import hashlib

# BUF_SIZE is totally arbitrary, change for your app!
BUF_SIZE = 65536  # Let’s read stuff in 64 kilobyte chunks

# Iterate over all JavaScript files in the folder and combine them
filenames = []
shortfilenames = []

imgfilenames = []
imgshortfilenames = []

# Get a unified path so we can stop dancing with user paths.
# Determine where files are on this machine (%TEMP% directory and application installation directory)
if '.exe' in sys.argv[0]: # if getattr(sys, 'frozen', False):
    RootPath = os.path.abspath(os.path.join(__file__, "..\\"))

elif __file__:
    RootPath = os.path.abspath(os.path.join(__file__, "..\\"))

print ("\n storage of image files RootPath: %s\n" %RootPath)

FolderPath = "D:\\TFS-FARM1\\StoneSoup_STS\\SDLC\\Build\\Code\\StoneSoup_Refactor\\StoneSoupUI\\Images"
print ("\n storage of image files in folder to search: %s\n" %FolderPath)

for root, directories, filenames2 in os.walk(FolderPath):
    for filename in filenames2:
        fullname = os.path.join(root, filename)
        filenames.append(fullname)
        shortfilenames.append(filename)

for i, fname in enumerate(shortfilenames):
        print("%s - %s" % (i+1, fname))

for root, directories, filenames2 in os.walk(RootPath):
    for filename in filenames2:
        fullname = os.path.join(root, filename)
        imgfilenames.append(fullname)
        imgshortfilenames.append(filename)

for i, fname in enumerate(imgshortfilenames):
        print("%s - %s" % (i+1, fname))

for i, fname in enumerate(imgshortfilenames):
        if fname in shortfilenames:
            print("%s - %s exists" % (i+1, fname))
        else:
            print("%s - %s ABSENT" % (i+1, fname))