大约有 47,000 项符合查询结果（耗时：0.0261秒） [XML]
How to delete history of last 10 commands in shell?
Commands follows
18 Answers
18
...
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...
Which MySQL data type to use for storing boolean values
...
For MySQL 5.0.3 and higher, you can use BIT. The manual says:
As of MySQL 5.0.3, the BIT data type is used to store bit-field
values. A type of BIT(M) enables storage of M-bit values. M can range
from 1 to 64.
Otherwise, according to the M...
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
...
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...
Algorithm to generate a crossword
...Basically:
Sort all the words by length, descending.
Take the first word and place it on the board.
Take the next word.
Search through all the words that are already on the board and see if there are any possible intersections (any common letters) with this word.
If there is a possible location fo...
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...
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...
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.
...