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Best explanation for languages without null

...f why null is undesirable is that meaningless states should not be representable. Suppose I'm modeling a door. It can be in one of three states: open, shut but unlocked, and shut and locked. Now I could model it along the lines of class Door private bool isShut private bool isLocked an...
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How to implement a Map with multiple keys? [duplicate]

...nother solution is to use Google's Guava import com.google.common.collect.Table; import com.google.common.collect.HashBasedTable; Table<String, String, Integer> table = HashBasedTable.create(); The usage is really simple: String row = "a"; String column = "b"; int value = 1; if (!table.c...
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How to do an update + join in PostgreSQL?

...ATE syntax is: [ WITH [ RECURSIVE ] with_query [, ...] ] UPDATE [ ONLY ] table [ [ AS ] alias ] SET { column = { expression | DEFAULT } | ( column [, ...] ) = ( { expression | DEFAULT } [, ...] ) } [, ...] [ FROM from_list ] [ WHERE condition | WHERE CURRENT OF cursor_name ] ...
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Is BCrypt a good hashing algorithm to use in C#? Where can I find it? [closed]

...ing through the use of the same encryption key that encrypted it. Rainbow Table - a lookup table that contains all variations of characters hashed in a specific hashing algorithm. Salt - a known random string appended to the original string before it is hashed. For the .NET Framework, Bcrypt does...
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MySQL join with where clause

I have two tables I want to join. 2 Answers 2 ...
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Defeating a Poker Bot

... and patterns (i.e., worst case scenario is a player who plays 24x7 and 16 tables continuously, there is a tiny tiny chance this is a real human. (However some players do have the ability to play very large hand volumes which to the inexperienced eye would appear to be a bot) Throw it glitches. If ...
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How can I select from list of values in SQL Server

...g them: [MS official] https://docs.microsoft.com/en-us/sql/t-sql/queries/table-value-constructor-transact-sql http://www.sql-server-helper.com/sql-server-2008/row-value-constructor-as-derived-table.aspx share | ...
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Why isn't SQL ANSI-92 standard better adopted over ANSI-89?

...e one and the USING Clause is another. IMHO, the addition of a column to a table shouldn't break code but a NATURAL JOIN breaks in a most egregious fashion. The "best" way to break is by compilation error. For example if you SELECT * somewhere, the addition of a column could fail to compile. The nex...
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Why would anyone use set instead of unordered_set?

... and many other places. What I understand is that unordered_set is hash table with O(1) lookup complexity. On the other hand, set is nothing but a tree with log(n) lookup complexity. Why on earth would anyone use set instead of unordered_set? i.e is there a need for set anymore? ...
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How to read a CSV file into a .NET Datatable

How can I load a CSV file into a System.Data.DataTable , creating the datatable based on the CSV file? 22 Answers ...