大约有 47,000 项符合查询结果（耗时：0.0693秒） [XML]
What's the difference between equal?, eql?, ===, and ==?
...reat explanations. I encourage you to read it, and also the documentation for these methods as they're overridden in other classes, like String.
Side note: if you want to try these out for yourself on different objects, use something like this:
class Object
def all_equals(o)
ops = [:==, :===, ...
Can't escape the backslash with regex?
... (because the string parser will remove two of them when "de-escaping" it for the string, and then the regex needs two for an escaped regex backslash).
For instance:
regex("\\\\")
is interpreted as...
regex("\\" [escaped backslash] followed by "\\" [escaped backslash])
is interpreted as...
r...
MongoDB: How to query for records where field is null or not set?
...en:
db.emails.count({sent_at: {$exists: false}})
If its there and null, or not there at all:
db.emails.count({sent_at: null})
Refer here for querying and null
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Get item in the list in Scala?
How in the world do you get just an element at index i from the List in scala?
4 Answers
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Validate that a string is a positive integer
...
Two answers for you:
Based on parsing
Regular expression
Note that in both cases, I've interpreted "positive integer" to include 0, even though 0 is not positive. I include notes if you want to disallow 0.
Based on Parsing
If you wa...
How to make Java honor the DNS Caching Timeout?
We use GSLB for geo-distribution and load-balancing. Each service is assigned a fixed domain name. Through some DNS magic, the domain name is resolved into an IP that's closest to the server with least load. For the load-balancing to work, the application server needs to honor the TTL from DNS respo...
how to override left:0 using CSS or Jquery?
...
The default value for left is auto, so just set it to that and you will "reset" it.
.elem {
left: auto;
}
Make sure that the above comes after the original CSS file.
...
Regular expression search replace in Sublime Text 2
...
Usually a back-reference is either $1 or \1 (backslash one) for the first capture group (the first match of a pattern in parentheses), and indeed Sublime supports both syntaxes. So try:
my name used to be \1
or
my name used to be $1
Also note that your orig...
Print variables in hexadecimal or decimal format
...ry these:
# Hexadecimal
p/x variable
# Binary
p/t variable
See output formats.
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What does the caret operator (^) in Python do?
I ran across the caret operator in python today and trying it out, I got the following output:
5 Answers
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