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Is there a difference between single and double quotes in Java?
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Use single quotes for literal chars, double quotes for literal Strings, like so:
char c = 'a';
String s = "hello";
They cannot be used any other way around (like in Python, for example).
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Efficient way to remove ALL whitespace from String?
...s to remove all whitespace (including newlines) and doing this (XML is the string received from the web request):
16 Answer...
How to convert a data frame column to numeric type?
... char_fac = factor(letters[1:5]),
num = 1:5, stringsAsFactors = FALSE)
Let us have a glance at data.frame
> d
char fake_char fac char_fac num
1 a 1 1 a 1
2 b 2 2 b 2
3 c 3 3 c 3
4 d 4 ...
Keep-alive header clarification
...ween computer A and server F")?
A TCP connection is recognized by source IP and port and destination IP and port. Your OS, all intermediate session-aware devices and the server's OS will recognize the connection by this.
HTTP works with request-response: client connects to server, performs a requ...
Check if a string contains one of 10 characters
I'm using C# and I want to check if a string contains one of ten characters, *, &, # etc etc.
6 Answers
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What is the C# equivalent of NaN or IsNumeric?
What is the most efficient way of testing an input string whether it contains a numeric value (or conversely Not A Number)? I guess I can use Double.Parse or a regex (see below) but I was wondering if there is some built in way to do this, such as javascript's NaN() or IsNumeric() (was that VB...
Cannot ping AWS EC2 instance
...ill help someone else...
1) First make sure the EC2 instance has a public IP. If has a Public DNS or Public IP address (circled below) then you should be good. This will be the address you ping.
2) Next make sure the Amazon network rules allow Echo Requests. Go to the Security Group for the EC2.
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Why does string::compare return an int?
Why does string::compare return an int instead of a smaller type like short or char ? My understanding is that this method only returns -1, 0 or 1.
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What is the difference between std::array and std::vector? When do you use one over other? [duplicat
...t. Creating large objects on the stack is generally frowned upon, and the extra level of indirection is usually irrelevant. (For example, if you iterate through all of the elements, the extra memory access only happens once at the start of the loop.)
The vector's elements are guaranteed to be con...
Node.js + Nginx - What now?
...s-available/yourdomain.com
In it you should have something like:
# the IP(s) on which your node server is running. I chose port 3000.
upstream app_yourdomain {
server 127.0.0.1:3000;
keepalive 8;
}
# the nginx server instance
server {
listen 80;
listen [::]:80;
server_name y...