大约有 30,000 项符合查询结果（耗时：0.0268秒） [XML]
Efficient string concatenation in C++
...object is returned after each +. That means that a new buffer is used each time. If you are doing a ton of extra + operations it is not efficient.
Why you can make it more efficient:
You are guaranteeing efficiency instead of trusting a delegate to do it efficiently for you
the std::string clas...
How do I plot in real-time in a while loop using matplotlib?
I am trying to plot some data from a camera in real time using OpenCV. However, the real-time plotting (using matplotlib) doesn't seem to be working.
...
If strings are immutable in .NET, then why does Substring take O(n) time?
...e been designed such that string.Substring() takes O( substring.Length ) time, instead of O(1) ?
5 Answers
...
Asynchronous method call in Python?
...an use enhanced generators for async functions.
import asyncio
import datetime
Enhanced generator syntax:
@asyncio.coroutine
def display_date(loop):
end_time = loop.time() + 5.0
while True:
print(datetime.datetime.now())
if (loop.time() + 1.0) >= end_time:
...
How can I validate a string to only allow alphanumeric characters in it?
...at I will never remember the syntax. Even if I study it, there will come a time soon when it's all forgotten again.
– Sentinel
Jan 14 '15 at 17:26
1
...
Vim indent xml file
...
@hakunami i wish i could upvote you 1000 times for simplifying that process
– niken
Jul 16 '15 at 15:07
|
...
How to check if a line is blank using regex
... @adamlogan yeah, from memory, I think I wanted to do it at the time, but I didn't have enough reputation to comment on someone else's post, so had to do it like this.
– John Henry
Jun 27 '18 at 1:41
...
Error “initializer element is not constant” when trying to initialize variable with const
...nst char * str2 = str1;
In fact, a "const char *" string is not a compile-time constant, so it can't be an initializer. But a "const char * const" string is a compile-time constant, it should be able to be an initializer. I think this is a small drawback of CLang.
A function name is of course a co...
Declaring an unsigned int in Java
...gned can break CRC calculations etc. It's not a show stopper, just wasted time.
– Lorne K
Aug 25 '16 at 15:21
3
...
Bash Script: count unique lines in file
...t file:
$ for i in {1..100000}; do echo $RANDOM; done > random.txt
$ time sort random.txt | uniq | wc -l
31175
real 0m1.193s
user 0m0.701s
sys 0m0.388s
$ time awk '!seen[$0]++' random.txt | wc -l
31175
real 0m0.675s
user 0m0.108s
sys 0m0.171s
...