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What does Python's eval() do?
...was a trivial example, but you could let the user type in an arbitrary command and have python execute it. So you could have the user type in a command string and then have python run it as code. So for example: eval("__import__('os').remove('file')").
– BYS2
F...
How to install GCC piece by piece with GMP, MPFR, MPC, ELF, without shared libraries?
...s of dependencies, not using a package manager (like yum, rpm, apt, dpkg), and not using shared libraries?
6 Answers
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Converting between datetime, Timestamp and datetime64
...d by np.datetime64 as time in UTC.
To convert datetime to np.datetime64 and back (numpy-1.6):
>>> np.datetime64(datetime.utcnow()).astype(datetime)
datetime.datetime(2012, 12, 4, 13, 34, 52, 827542)
It works both on a single np.datetime64 object and a numpy array of np.datetime64.
Th...
Is APC compatible with PHP 5.4 or PHP 5.5?
...e the replacement for APC going forward as it is included in the PHP core, and will have to be maintained for each new release.
I would personally advise those who depend on APC for it's opcode caching to test their code with the upcoming built-in opcode cache, and feed back any issues encountered t...
Clang vs GCC - which produces faster binaries? [closed]
I'm currently using GCC, but I discovered Clang recently and I'm pondering switching. There is one deciding factor though - quality (speed, memory footprint, reliability) of binaries it produces - if gcc -O3 can produce a binary that runs 1% faster, or Clang binaries take up more memory or just fai...
subtle differences between JavaScript and Lua [closed]
...oesn't convert between types for any comparison operators. In JS, only === and !== don't type juggle.
Lua has an exponentiation operator (^); JS doesn't. JS uses different operators, including the ternary conditional operator (?: vs and/or), and, as of 5.3, bitwise operators (&, |, etc. vs. meta...
How can you determine a point is between two other points on a line segment?
Let's say you have a two dimensional plane with 2 points (called a and b) on it represented by an x integer and a y integer for each point.
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Constant Amortized Time
...erations". Amortised time doesn't have to be constant; you can have linear and logarithmic amortised time or whatever else.
Let's take mats' example of a dynamic array, to which you repeatedly add new items. Normally adding an item takes constant time (that is, O(1)). But each time the array is ful...
Finding duplicates in O(n) time and O(1) space
...ns in O(N) time. A swap only occurs if there is an i such that A[i] != i, and each swap sets at least one element such that A[i] == i, where that wasn't true before. This means that the total number of swaps (and thus the total number of executions of the while loop body) is at most N-1.
The seco...
Understanding how recursive functions work
...grok yet. Filtering out all of the (extremely clever) "In order to understand recursion, you must first understand recursion." replies from various online threads I still am not quite getting it.
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