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Join vs. sub-query
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@user1735921 IMO it depends ... Generally, it's very important the readability of the code, because it is of great importance for later management of it... Let's remember the famous statement of Donald Knuth: "Premature optimization is the root of all evil (or a...
What is Weak Head Normal Form?
... further (i.e. it contains no un-evaluated thunks).
These expressions are all in normal form:
42
(2, "hello")
\x -> (x + 1)
These expressions are not in normal form:
1 + 2 -- we could evaluate this to 3
(\x -> x + 1) 2 -- we could apply the function
"he" ++ "llo" ...
Error handling in C code
... your library as painless as possible think about these additions:
store all possible error-states in one typedef'ed enum and use it in your lib. Don't just return ints or even worse, mix ints or different enumerations with return-codes.
provide a function that converts errors into something huma...
Tips for a successful AppStore submission? [closed]
...Store.
Your bundle identifier, as sascha says, should be unique and is usually your domain backwards. This needs to match the App Id you created in the Developer Portal.
The Display Name (CFBundleDisplayName) is how it appears on the home screen. One important thing I found about this is that it c...
Why do we need Abstract factory design pattern?
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All of these examples describe the Factory Method Pattern, because all of them return a single product interface. None of these is an Abstract Factory Pattern, because none of them produce a family of related product interfac...
Importing variables from another file?
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from file1 import *
will import all objects and methods in file1
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Why does ~True result in -2?
...00000001
and ~1 is:
11111110
Which is -2 in Two's complement1
1 Flip all the bits, add 1 to the resulting number and interpret the result as a binary representation of the magnitude and add a negative sign (since the number begins with 1):
11111110 → 00000001 → 00000010
↑ ...
How to determine if binary tree is balanced?
... some fraction of the minimum path length, like a half or a quarter.
It really doesn't matter usually. The point of any tree-balancing algorithm is to ensure that you do not wind up in the situation where you have a million nodes on one side and three on the other. Donal's definition is fine in the...
How to make button look like a link?
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If you don't want all buttons to be styled as links, scope the style with something like button.link {...styles...} then <button class="link">Your button</button>. This also avoids using !important which is always a good idea.
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`from … import` vs `import .` [duplicate]
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I just tried import urllib.request and it doesn't work at all (python 2.6.5 Ubuntu).
– tkone
Feb 24 '12 at 23:33
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