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how to concatenate two dictionaries to create a new one in Python? [duplicate]
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Unless all keys are known to be strings, option 2 is an abuse of a Python 2 implementation detail (the fact that some builtins implemented in C bypassed the expected checks on keyword arguments). In Python 3 (and in PyPy), option 2 will fail with non-string...
Why / when would it be appropriate to override ToString?
I'm studying C# and I wonder what the point and benefit of overriding ToString might be, as shown in the example below.
1...
MySQL indexes - what are the best practices?
...mpacts of indexing
UPDATEs and INSERTs will be slower. There's also the extra storage space requirments, but that's usual unimportant these days.
If i have a VARCHAR 2500 column which is searchable from parts of my site, should i index it
No, unless it's UNIQUE (which means it's already ind...
Passing properties by reference in C#
...Here are a few ways you can work around this limitation.
1. Return Value
string GetString(string input, string output)
{
if (!string.IsNullOrEmpty(input))
{
return input;
}
return output;
}
void Main()
{
var person = new Person();
person.Name = GetString("test", pe...
Convert base-2 binary number string to int
I'd simply like to convert a base-2 binary number string into an int, something like this:
8 Answers
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Capturing Groups From a Grep RegEx
... name="${BASH_REMATCH[1]}"
echo "${name}.jpg" # concatenate strings
name="${name}.jpg" # same thing stored in a variable
else
echo "$f doesn't match" >&2 # this could get noisy if there are a lot of non-matching files
fi
done
It's better to put the ...
if a ngSrc path resolves to a 404, is there a way to fallback to a default?
... Works well if the url is broken (404), but if it's an empty string ng-src silently swallows the error.
– Stephen Patten
Sep 18 '13 at 18:43
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write a shell script to ssh to a remote machine and execute commands
...andard output and standard error as each host completes
-x args: Passes extra SSH command-line arguments
-o option: Can be used to give options in the format used in the configuration file.(/etc/ssh/ssh_config) (~/.ssh/config)
-p parallelism: Use the given number as the maximum number of con...
The Ruby %r{ } expression
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this regexp matches all strings that ends with .gif, .jpg...
you could replace it with
/\.(gif|jpg|jpeg|png)$/i
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Why can tuples contain mutable items?
...der one roof. For example,
s = ('www.python.org', 80)
brings together a string and a number so that the host/port pair can be passed around as a socket, a composite object. Viewed in that light, it is perfectly reasonable to have mutable components.
Immutability goes hand-in-hand with another pr...