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Bad arguments to +：The operation + cannot accept the arguments:, [&qu...
原因是加号+前面是空字符串，不能有效地转换成数字，所以报错。
比如"123"这个字符串可以自动转数字，但是空文本不行。
文本要判断空，然后给数字 0。
同理，空文本不但不能转数字，也不能转列表、字典...
Apache Spark: The number of cores vs. the number of executors
...So the number 5 isn't something I came up with: I just noticed signs of IO bottlenecking and went off in search of where those bottlenecks may be coming from.
– turtlemonvh
Oct 14 '19 at 19:28
...
Should you ever use protected member variables?
... something worth worrying about unless you find through profiling that the bottle neck ends up being the accessors (which it almost never is). There are tricks that can be done to make the JIT smarter about things if it ends up being an issue. In java for example you can hint that the accessor can b...
What are important languages to learn to understand different approaches and concepts? [closed]
When all you have is a pair of bolt cutters and a bottle of vodka, everything looks like the lock on the door of Wolf Blitzer's boathouse. (Replace that with a hammer and a nail if you don't read xkcd)
...
Why should Java ThreadLocal variables be static
...mmonPool-worker-2->31->31
Start-ForkJoinPool.commonPool-worker-3->81->81
Start-ForkJoinPool.commonPool-worker-1->87->87
End-main->62->62
End-ForkJoinPool.commonPool-worker-1->87->87
End-ForkJoinPool.commonPool-worker-2->31->31
End-ForkJoinPool.commonPool-worker-3-...
How to increase the gap between text and underlining in CSS
...e: linear-gradient(
180deg, rgba(0,0,0,0),
rgba(0,0,0,0) 81%,
#222222 81.1%,
#222222 85%,
rgba(0,0,0,0) 85.1%,
rgba(0,0,0,0)
);
text-decoration: none;
}
<a href="#">Lorem ipsum</a> dolor sit amet, <a href="#">conset...
Beyond Stack Sampling: C++ Profilers
...portions of your code that are CPU bound. Which is awesome if that is the bottle neck in your application. Not so great if your application threads spend most of their time fighting over a mutex.
A time sampling profiler grabs a stack trace every N microseconds.
This technique will zero in on "slo...
“fatal: Not a git repository (or any of the parent directories)” from git status
...
Michael DurrantMichael Durrant
81.2k7676 gold badges278278 silver badges402402 bronze badges
...
super() fails with error: TypeError “argument 1 must be type, not classobj” when parent does not inh
...
interesting, I found this exact problem running bottle.py (bottlepy.org) which throws a similar error (TypeError: must be type, not classobj) running on Py27 but not Py33.
– bootload
Sep 3 '13 at 7:35
...
Is there a performance impact when calling ToList()?
...ehavior affects little on performance. It's impossible to be a performance bottle neck of your application.
What's wrong with the code in the question
Directory.GetFiles goes through the folder and returns all files' names immediately into memory, it has a potential risk that the string[] costs a ...