大约有 40,000 项符合查询结果（耗时：0.0285秒） [XML]
What does the regular expression /_/g mean?
...egex matches the _ character.
The g means Global, and causes the replace call to replace all matches, not just the first one.
share
|
improve this answer
|
follow
...
mongodb group values by multiple fields
... $slice just off the basic aggregation result. For "large" results, run parallel queries instead for each grouping ( a demonstration listing is at the end of the answer ), or wait for SERVER-9377 to resolve, which would allow a "limit" to the number of items to $push to an array.
db.books.aggregate(...
Private properties in JavaScript ES6 classes
...class fields work. You can't currently use this in constructor before you call super(). Yet babel puts them before super.
– seeker_of_bacon
Oct 3 '18 at 16:23
...
Why is printing to stdout so slow? Can it be sped up?
...ing I decided to look into it and was quite surprised to find that almost all the time spent is waiting for the terminal to process the results.
...
Behaviour of increment and decrement operators in Python
...e applied on a variable (like ++count ). It compiles, but it does not actually change the value of the variable!
9 Answers...
Execute the setInterval function without delay the first time
...
It's simplest to just call the function yourself directly the first time:
foo();
setInterval(foo, delay);
However there are good reasons to avoid setInterval - in particular in some circumstances a whole load of setInterval events can arrive imm...
How to validate an email address in JavaScript
...b"@gmail.com, _@gmail.com, 1@gmail.com , 1_example@something.gmail.com are all valid, but Gmail will never allow any of these email addresses. You should do this by accepting the email address and sending an email message to that email address, with a code/link the user must visit to confirm validit...
How does type Dynamic work and how to use it?
...
Scalas type Dynamic allows you to call methods on objects that don't exist or in other words it is a replica of "method missing" in dynamic languages.
It is correct, scala.Dynamic doesn't have any members, it is just a marker interface - the co...
Delete files older than 15 days using PowerShell
...is in the title of this post), but here's some code that will first delete all of the files older than 15 days, and then recursively delete any empty directories that may have been left behind. My code also uses the -Force option to delete hidden and read-only files as well. Also, I chose to not use...
Python: try statement in a single line
...ther dynamic languages. The safer way (and the prevailing style) is to set all variables to something. If they might not get set, set them to None first (or 0 or '' or something if it is more applicable.)
If you do assign all the names you are interested in first, you do have options.
The best...