Getting error java.lang.NullPointerException: Attempt to invoke interface method ‘int java.util.List.size()’ on a null object reference [duplicate]

This question already has an answer here: What is a NullPointerException, and how do I fix it? 12 answers I am getting the error: java.lang.NullPointerException: Attempt to invoke interface method ‘int java.util.List.size()’ on a null object reference . I am trying to figure out the exact problem but unable to pinpoint the exact location. Was…

Details

The question on iterator begin() function

Below the link where I see how iterator begin function works but not understand clearly. https://secweb.cs.odu.edu/~zeil/cs361/web/website/Lectures/iterators/pages/implem.html In their, I see begin function but don’t understand how it works Book::iterator Book::begin() { Book::iterator it; it->pos = authors; return it; }; in this it is object but in this it-> what is doing i think this overloaded…

Details

Unable to import sklearn in python, showing ImportError: DLL load failed

Using a conda setup in windows from sklearn.ensemble import RandomForestClassifier Output ImportError Traceback (most recent call last) <ipython-input-4-d78f0aaa3480> in <module>() —-> 1 from sklearn import * C:\Users\ashish\Anaconda2\envs\py35\lib\site-packages\sklearn\__init__.py in <module>() 71 ‘clone’] 72 —> 73 from .daal4sklearn import dispatcher 74 dispatcher.enable() 75 C:\Users\ashish\Anaconda2\envs\py35\lib\site-packages\sklearn\daal4sklearn\dispatcher.py in <module>() 7 from ..linear_model.ridge import Ridge 8 —-> 9 from .k_means import…

Details

how to get url parameter in modelform

I have one model name is cityform i want to get url parmeter in this CityFrom hwo can i do this? here is my url path(‘state/city/<int:id>/’, City.as_view(), name=”city”) http://localhost:8000/country/state/city/3/ here is my form class CityFrom(forms.ModelForm): def __init__(self, *args, **kwargs): super(CityFrom,self).__init__(*args, **kwargs) print(args) print(kwargs) self.fields[‘state’] = forms.ModelChoiceField( empty_label = ‘Select’, queryset = State.objects.all() ) class Meta:…

Details