print和wri的不同结果

Question

我有下面的函数，它将先前构造的文件读入defaultdict。它读取的文件是csv文件，包含文件大小和文件路径

如果有多个文件与另一个文件的文件大小匹配，则该文件将通过哈希函数运行

我的问题是，print给了我预期的输出，而将输出写入文件则不是

def loadfiles():
    '''Loads files and identifies potential duplicates'''
    files = defaultdict(list)  # uses defaultdict
    with open(tmpfile) as csvfile:  # reads the file into a dictionary
        reader = csv.DictReader(csvfile)
        for row in reader:
            files[row['size']].append(row['file'])
        for key, value in files.items():
            if len([item for item in value if item]) > 1:
                with open (reportname, 'w') as fr:
                    writer = csv.writer(fr, delimiter=',', quotechar='"', quoting=csv.QUOTE_MINIMAL)
                    writer.writerow(['size','filename','hash'])
                    for value in value:
                        writer.writerow([key,value,str(md5Checksum(value))])
                        print(key, value, str(md5Checksum(value)))

文件的输出如下：

size,filename,hash

43842270,/home/bob/scripts/inprogress_python_scripts/file_dup/testingscript/webwolf-8.0.0.M25.jar,b325dc62d33e2ada19aea07cbcfb237f

43842270,/home/bob/scripts/inprogress_python_scripts/file_dup/testingscript/bkwolf.jar,b325dc62d33e2ada19aea07cbcfb237f

其中，从print到screen的输出是：

128555 /home/bob/scripts/inprogress_python_scripts/file_dup/testingscript/SN0aaa(1).pdf def426a8dee8f226e40df826fcde9904

128555 /home/bob/scripts/inprogress_python_scripts/file_dup/testingscript/SN0aaa(1) (another copy).pdf def426a8dee8f226e40df826fcde9904

128555 /home/bob/scripts/inprogress_python_scripts/file_dup/testingscript/SN0aaa.pdf def426a8dee8f226e40df826fcde9904

128555 /home/bob/scripts/inprogress_python_scripts/file_dup/testingscript/SN0aaa(1) (copy).pdf def426a8dee8f226e40df826fcde9904

43842270 /home/bob/scripts/inprogress_python_scripts/file_dup/testingscript/webwolf-8.0.0.M25.jar b325dc62d33e2ada19aea07cbcfb237f

43842270 /home/b/scripts/inprogress_python_scripts/file_dup/testingscript/bkwolf.jar b325dc62d33e2ada19aea07cbcfb237f

有什么问题吗

Answer 1

使用“w”以写模式打开文件，覆盖文件中已经存在的任何内容。用“a”代替append

这将导致一个问题，你将有你的头（大小，文件名，哈希）在那里多次-考虑写在第一行，而不是在一个循环

参见，例如：https://www.w3schools.com/python/python_file_write.asp