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Unique combination of all elements from two (or more) vectors
I am trying to create a unique combination of all elements from two vectors of different size in R.
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In Postgresql, force unique on combination of two columns
I would like to set up a table in PostgreSQL such that two columns together must be unique. There can be multiple values of either value, so long as there are not two that share both.
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Is an index needed for a primary key in SQLite?
When an integer column is marked as a primary key in an SQLite table, should an index be explicitly created for it as well? SQLite does not appear to automatically create an index for a primary key column, but perhaps it indexes it anyway, given its purpose? (I will be searching on that column all t...
Ruby on Rails: How do I add placeholder text to a f.text_field?
How can I add placeholder text to my f.text_field fields so that the text comes pre-written by default, and when a user click inside the fields, the text goes away - allowing the user to type in the new text?
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MySQL remove all whitespaces from the entire column
Is there a way to remove all whitespaces from a specific column for all values?
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How to identify whether a file is normal file or directory
How do you check whether a file is a normal file or a directory using python?
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Which concurrent Queue implementation should I use in Java?
From the JavaDocs:
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Edit a commit message in SourceTree Windows (already pushed to remote)
How do I edit an incorrect commit message in SourceTree without touching the command line?
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How to retrieve form values from HTTPPOST, dictionary or?
I have an MVC controller that has this Action Method:
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How to put comments in Django templates
I would like to comment this with a line
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