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Explain the encapsulated anonymous function syntax
...ression:
(function foo() {
alert(2 + 2);
}());
The Parentheses (formally called the Grouping Operator) can surround only expressions, and a function expression is evaluated.
The two grammar productions can be ambiguous, and they can look exactly the same, for example:
function foo () {} // ...
ValueError: setting an array element with a sequence
...uple into a numpy
#array element
def foo():
return 3
numpy.array([2, foo()]) #good
def foo():
return [3,4]
numpy.array([2, foo()]) #Fail, can't convert a list into a numpy
#array element
2. B...
Set a path variable with spaces in the path in a Windows .cmd file or batch file
...
this should be the accepted answer. for some reason, calling set from an if block doesn't work if the value has a space and is unquoted.
– Kevin
Aug 1 '19 at 16:35
...
When to encode space to plus (+) or %20?
...value is query value with a space, but the folder name in the path is literally foo+bar, not foo bar.
%20 is a valid way to encode a space in either of these contexts. So if you need to URL-encode a string for inclusion in part of a URL, it is always safe to replace spaces with %20 and pluses with ...
close vs shutdown socket?
...both sending and receiving (like close). However, close is the way to actually destroy a socket.
With shutdown, you will still be able to receive pending data the peer already sent (thanks to Joey Adams for noting this).
s...
What's the difference between URI.escape and CGI.escape?
...
There were some small differences, but the important point is that URI.escape has been deprecated in Ruby 1.9.2... so use CGI::escape or ERB::Util.url_encode.
There is a long discussion on ruby-core for those interested which also mentions WE...
How do I append one string to another in Python?
...ugh memory to resize the string, the original
string object at *pv is deallocated, *pv is set to NULL, an "out of
memory" exception is set, and -1 is returned. Else (on success) 0 is
returned, and the value in *pv may or may not be the same as on input.
As always, an extra byte is alloc...
node.js hash string?
... If I have lots of strings to hash, it is less efficient to keep calling crypto.createHash instead of somehow re-using the result?
– Michael
Mar 28 '19 at 3:23
add a ...
Selecting multiple columns in a pandas dataframe
...).
df1 = df[['a', 'b']]
Alternatively, if it matters to index them numerically and not by their name (say your code should automatically do this without knowing the names of the first two columns) then you can do this instead:
df1 = df.iloc[:, 0:2] # Remember that Python does not slice inclusive of...
Using PHP with Socket.io
...t there are some ways to implement WebSockets. There is this jQuery plugin allowing you to use Websockets while gracefully degrading for non-supporting browsers. On the PHP side, there is this class which seems to be the most widely used for PHP WS servers.
...