Phenomenon When I try to add data to the database using sqlite3 in python, I get "Operational Error: no such column: None". It reproduce...

Task I'm making an app that uses Android's Bottom Navigation. I want to save the data written in TextView etc. when I move the page and...

What I want to do I want to determine if a given string is a number. Problem Python has a method called isnumeric () that determines...

Situation I want to get a list of files and folders directly under the directory by os.listdir () and operate on the folders in it....

Situation As the title says, when I put a DropdownButton inside a Row with flutter, I get an exception of "A RenderFlex overflowed"....

Situation When I try to convert a character string representing the time to DateTime type with parse () method of DateFormat with...

Overview I'm making a smartphone app with flutter. Redux is used for state management. I want to write the data in the shared preference...

Overview I'm making a smartphone app with flutter. Redux is used for state management. Save the data I want to keep even if the...

Situation The above error occurs when trying to plot the data stored in the DataFrame of pandas. Cause The data type was object. The...

Situation (It's a mistake to say from the conclusion ...) I convert DateTime type variable to String with dart and save it in shared...

Situation There is a class that regulates the operation of the application. The "Change settings" screen takes a copy of the existing...