In Python we frequently need to check if a value is in an array (list) or not. Pythonx in listcan be used for checking if a value is in a list. Note that the value type must also match. Here is a quick example: a = ["1", "2", "3"] if "2" in a: print "string 2 i...
# 使用列表推导式判断多个值是否存在fruits=['apple','banana','orange']items_to_check=['apple','grape','watermelon']exist_items=[itemforiteminitems_to_checkifiteminfruits]print('存在的水果:',exist_items) 1. 2. 3. 4. 5. 6. 在上面的示例中,我们利用列表推导式一次性判断了多个值是否存在...
# 使用字典判断一个变量是否等于多个值value=3values_dict={1:"The value is equal to 1.",2:"The value is equal to 2.",3:"The value is equal to 3.",4:"The value is equal to 4."}ifvalueinvalues_dict:print(values_dict[value])else:print("The value is not equal to any of the s...
查看4是否在列表中(使用循环):存在查看4是否在列表中(使用in关键字):存在 实例2 # 初始化列表 test_list_set=[1,6,3,5,3,4] test_list_bisect=[1,6,3,5,3,4] print("查看 4 是否在列表中 ( 使用 set() + in) : ") test_list_set=set(test_list_set) if4intest_list_set : print("...
{'file-operation': 'urn:huawei:yang:huawei-file-operation'} mpath = '{}'.format('dir') for file_tmp in root_elem.findall(mpath, namespaces): file_name = file_tmp.find("file-name", namespaces) elem = file_tmp.find("dir-name", namespaces) if elem is None or file_name is None:...
The 'in' OperatorThe in operator in Python is the most straightforward and idiomatic way to check if an element exists in a list. This operator performs a membership test, returning True if the specified element is present in the list and False otherwise. Its simplicity and readability make ...
Now, call the “print()” function to view the input value of string and list: print("My input string is : "+ first_str) print("My initialized list is : "+str(var_list)) Use the “for” loop and check the condition with “if” statement from the input string: ...
defis_empty(self):""" Return True if array is empty"""returnself.n==0def__len__(self):"""Return numbers of elements stored in the array."""returnself.n def__getitem__(self,i):"""Return element at index i."""ifnot0<=i<self.n:# Check it i index isinboundsofarray ...
Py_DECREF(obj);if(cmp >0)returnPyLong_FromSsize_t(i);elseif(cmp <0)returnNULL; } PyErr_Format(PyExc_ValueError,"%R is not in list", value);returnNULL; } 这是python源码中,实现的从list中查找一个元素是否存在,并返回这个元素第一次出现下标的具体实现。可以看到这里是使用for循环,从头到尾的...
installalso creates${prefix}/bin/python3which refers to${prefix}/bin/python3.X. If you intend to install multiple versions using the same prefix you must decide which version (if any) is your "primary" version. Install that version usingmake install. Install all other versions usingmake ...