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How do SQL EXISTS statements work?
...del
Let’s assume we have the following two tables in our database, that form a one-to-many table relationship.
The student table is the parent, and the student_grade is the child table since it has a student_id Foreign Key column referencing the id Primary Key column in the student table.
The...
Add column with number of days between dates in DataFrame pandas
...days) will give you the -58 you seek.
If your columns aren't in datetime format. The shorter syntax would be: df.A = pd.to_datetime(df.A)
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How is mime type of an uploaded file determined by browser?
...ypeFromExtension
// OK. We want to try the following sources of mimetype information, in this order:
// 1. defaultMimeEntries array
// 2. User-set preferences (managed by the handler service)
// 3. OS-provided information
// 4. our "extras" array
// 5. Information from plugins
// 6. The "ext-to-type...
What is the difference between supervised learning and unsupervised learning? [closed]
...answer mentions it (though, in an incorrect way): there are "intermediate" forms of supervision, i.e. semi-supervised and active learning. Technically, these are supervised methods in which there is some "smart" way to avoid a large number of labeled examples. In active learning, the algorithm itsel...
What is the difference (if any) between Html.Partial(view, model) and Html.RenderPartial(view,model)
...he difference is the return type, as SLaks said. This is non-trivial. Performance-wise, it's been claimed that rendering directly to the output stream is better (which was why they went w/ the void RenderPartial to start with). Partial is mostly useful (imo) in testing, though as SLaks said there...
Why is null an object and what's the difference between null and undefined?
...any undefined variable, however, name is a property of just about any HTML form element. It goes way, way back and was instituted well before id. It is useful because ids must be unique but names do not have to be.
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String.replaceAll single backslashes with double backslashes
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Get/pick an image from Android's built-in Gallery app programmatically
...his is a complete solution. I've just updated this example code with the information provided in the answer below by @mad. Also check the solution below from @Khobaib explaining how to deal with picasa images.
Update
I've just reviewed my original answer and created a simple Android Studio project...
What is the difference between a regular string and a verbatim string?
... 2.4.4.5 of the C# specification:
2.4.4.5 String literals
C# supports two forms of string literals: regular string literals and verbatim string literals.
A regular string literal consists of zero or more characters enclosed in double quotes, as in "hello", and may include both simple escape sequenc...
The differences between .build, .create, and .create! and when should they be used?
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