大约有 30,000 项符合查询结果（耗时：0.0247秒） [XML]
“INSERT IGNORE” vs “INSERT … ON DUPLICATE KEY UPDATE”
...,029,941 to 46,271,740 between two rows. That generation of a new AI every time means that your range can very quickly be filled and you need to clean up. This table is only two weeks old!
– Engineer81
Jul 10 '14 at 18:21
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Pointer to class data member “::*”
...tructure that represents the data you are collecting:
struct Sample {
time_t time;
double value1;
double value2;
double value3;
};
Now suppose that you stuff them into a vector:
std::vector<Sample> samples;
... fill the vector ...
Now suppose that you want to calculate so...
Why does C++11's lambda require “mutable” keyword for capture-by-value, by default?
...because by default, a function object should produce the same result every time it's called. This is the difference between an object orientated function and a function using a global variable, effectively.
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Verifying a specific parameter with Moq
...erify(c => c.Method(It.IsAny<int>(), It.IsAny<MyObject>()), Times.Once());
// Assert about saveObject
Assert.That(saveObject.TheProperty, Is.EqualTo(2));
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Perform an action in every sub-directory using Bash
...esn't print each word in a folder name as a separate entity.
# Option A
$ time for D in ./big_dir/*; do find "$D" -type d > /dev/null; done
real 0m0.327s
user 0m0.084s
sys 0m0.236s
# Option B
$ time for D in `find ./big_dir/* -type d`; do echo "$D" > /dev/null; done
real 0m0.787...
What's the difference between an object initializer and a constructor?
...t a variable when using an initializer list, you won't notice it until run-time (and maybe not even immediately). Furthermore: the field can't be readonly, making accidental changes possible, without the compiler complaining
– Harald Coppoolse
Jan 19 '17 at 9:1...
When is it practical to use Depth-First Search (DFS) vs Breadth-First Search (BFS)? [closed]
... solutions are rare, depth first search
(DFS) might take an extremely long time, but BFS could be faster.
If the tree is very wide, a BFS might need too much memory, so it
might be completely impractical.
If solutions are frequent but located deep in the tree, BFS could be
impractical.
If the sea...
Getting a timestamp for today at midnight?
How would I go about getting a timestamp in php for today at midnight. Say it's monday 5PM and I want the Timestamp for Monday(today) at midnight(12 am) which already has happened.
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List Git aliases
...ias called (strangely enough) alias for exactly this purpose... handy from time to time if you use aliasing enough...
$ git config --global alias.alias "config --get-regexp ^alias\."
Note, the regex makes sure the line starts with alias..
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Standard concise way to copy a file in Java?
...VisitDirectory(Path dir, IOException exc) {
// fix up modification time of directory when done
if (exc == null && Arrays.toList(options).contains(COPY_ATTRIBUTES)) {
Path newdir = target.resolve(source.relativize(dir));
try {
FileTime t...