之所以在写法二中可以用if直接判断列表a是否为空,是因为对于list来说,它没有内建方法__bool__(),而有内建方法__len__(),最后通过判断list长度是否为 0 来得出true或者false的,一旦为空,则判断结果为false
You can simply check if the List is empty with:if not my_list: print("List is empty") This is using the Truth Value Testing in Python, also known as implicit booleaness or truthy/falsy value testing.Among other rules it defines that empty sequences and collections like '', (), [],...
以下是一个示例代码: defcheck_empty_value(input_list):forelementininput_list:ifelementisNoneorelement=="":returnTruereturnFalsemy_list=[1,2,3,"",5]result=check_empty_value(my_list)print(result)# 输出 True 1. 2. 3. 4. 5. 6. 7. 8. 9. 在上面的代码中,我们定义了一个名为check_emp...
fruits = [] if fruits: for fruit in fruits: if fruit == 'apples': print('Sorry, we are out of apples right now.') else: print(fruit.title() + ' are available.') else: print('The list is empty.') 输出结果如下图所示。 3.使用多个列表 我们买东西时会自己先列一个清单,然后商店...
/* Check for overflow without an actual overflow, * which can cause compiler to optimise out */ if ((size_t)size > PY_SIZE_MAX / sizeof(PyObject *)) return PyErr_NoMemory(); nbytes = size * sizeof(PyObject *); // 如果 numfree 不等于 0 那么说明现在 free_list 有之前使用被释放...
在Python中,empty函数的定义如下: defempty(obj):''' 判断一个对象是否为空 参数: obj:需要判断的对象 返回值: 如果对象为空,则返回True;否则返回False '''ifobjisNone:returnTrueifisinstance(obj,(list,tuple,str)):returnlen(obj)==0ifisinstance(obj,dict):returnlen(obj.keys())==0returnFalse ...
if sys.version_info >= (3,): def clear(self) -> None: ... def copy(self) -> List[_T]: ... def append(self, object: _T) -> None: ... def extend(self, iterable: Iterable[_T]) -> None: ... def pop(self, index: int = ...) -> _T: ... ...
(uri, req_data) if ops_return_result(ret): logging.error('Copy file failed.') return ERR return OK def get_file_list_cur(types=0): filelist = [] fileNames = glob.glob(FLASH_HOME_PATH + r"/*.*") try: for fileName in fileNames: name = os.path.basename(fileName) filelist....
To check if NumPy array is empty in Python, we can use some functions like the size() function will provide the number of elements in the array, any() provides boolean values if any True value is present inside the array, shape() provides the dimension of the array, and tolist() will...
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