Question

我需要帮助。如果没有文件，函数必须返回“None”而不是“False”。对不起我的英文）

def file_search(folder, filename):
way=folder[0]
if filename in folder:
            return way+'/'+filename
for item in folder:

    if isinstance(item,list):
        found_file=file_search(item,filename)
        if found_file!=None:
            return way + '/' + found_file
print file_search([ 'D:', ['recycle bin'], ['tmp', ['old'], ['new folder1', 'asd.txt', 'asd.bak', 'find.me.bak' ] ], 'hey.py'], 'find.me')

Answer 1

只需在函数末尾加上“return False”。

目前，如果你的'if'语句失败，那么它没有返回语句，因此该函数默认返回None。

Answer 2

def file_search(folder, filename):
way=folder[0]
if filename in folder:
        return way+'/'+filename
for item in folder:

if isinstance(item,list):
    found_file=file_search(item,filename)
    if found_file!=None:
        return way + '/' + found_file
print file_search([ 'D:', ['recycle bin'], ['tmp', ['old'], ['new folder1', 'asd.txt', 'asd.bak', 'find.me.bak' ] ], 'hey.py'], 'find.me')
else: 
    return False

Answer 3

愚蠢的错误）默认函数应该返回False，我忘了检查（8行）来修复None - ＆gt;假

def file_search(folder, filename):
way=folder[0]
if filename in folder:
    return way+'/'+filename
for item in folder:
    if isinstance(item,list):
        found_file=file_search(item,filename)
        if found_file!=False:
            return way + '/' + found_file
return False

python函数必须不返回＆＃34;无＆＃34;但是＆＃34;错误＆＃34;

3 个答案: