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What is better, adjacency lists or adjacency matrices for graph problems in C++?
...ts or adjacency matrix, for graph problems in C++?
What are the advantages and disadvantages of each?
11 Answers
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bash: mkvirtualenv: command not found
...erage the chance that virtualenvwrapper.sh is already in your shell's PATH and just issue a source `which virtualenvwrapper.sh`
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Python != operation vs “is not”
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== is an equality test. It checks whether the right hand side and the left hand side are equal objects (according to their __eq__ or __cmp__ methods.)
is is an identity test. It checks whether the right hand side and the left hand side are the very same object. No methodcalls ...
Delete an element from a dictionary
... del/assignment/etc. means you're going from constant time to linear time, and also using linear space. For small dicts, this is not a problem. But if you're planning to make lots of copies of large dicts, you probably want a different data structure, like a HAMT (as described in this answer).
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Python: reload component Y imported with 'from X import Y'?
...nce I have imported a module X in an interpreter session using import X , and the module changes on the outside, I can reload the module with reload(X) . The changes then become available in my interpreter session.
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In javascript, is an empty string always false as a boolean?
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Yes. Javascript is a dialect of ECMAScript, and ECMAScript language specification clearly defines this behavior:
ToBoolean
The result is false if the argument is the empty String (its length is zero);
otherwise the result is true
Quote taken from http://www.ecma-inte...
What are the best practices for using a GUID as a primary key, specifically regarding performance?
...have an application that uses GUID as the Primary Key in almost all tables and I have read that there are issues about performance when using GUID as Primary Key. Honestly, I haven't seen any problem, but I'm about to start a new application and I still want to use the GUIDs as the Primary Keys, but...
What's a concise way to check that environment variables are set in a Unix shell script?
...(an empty string) is OK — not exactly what you want, but the alternative and older notation.
The second variant (using :?) requires DEST to be set and non-empty.
If you supply no message, the shell provides a default message.
The ${var?} construct is portable back to Version 7 UNIX and the Bourne ...
Delete all local git branches
...ry new feature or story card. When finished I merge the branch into master and then push.
25 Answers
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Declare and initialize a Dictionary in Typescript
...ke use of the typed dictionary by splitting your example up in declaration and initialization, like:
var persons: { [id: string] : IPerson; } = {};
persons["p1"] = { firstName: "F1", lastName: "L1" };
persons["p2"] = { firstName: "F2" }; // will result in an error
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