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Why do variable names often start with the letter 'm'? [duplicate]
...he Android tutorials such as the Notepad tutorial , I noticed that almost all variables are named starting with the letter 'm'. What convention is this, and where does it originate from?
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How to convert a data frame column to numeric type?
... and this is not the most confounding thing, but it can confuse you, especially if you read this before rolling into bed.
Here goes: first two columns are character. I've deliberately called 2nd one fake_char. Spot the similarity of this character variable with one that Dirk created in his reply. I...
How to Vertical align elements in a div?
I have a div with two images and an h1 . All of them need to be vertically aligned within the div, next to each other.
29 ...
Need a simple explanation of the inject method
...otal and then stores the result back into the accumulator. The next block call has this new value, adds to it, stores it again, and repeats.
At the end of the process, inject returns the accumulator, which in this case is the sum of all the values in the array, or 10.
Here's another simple example...
When to use next() and return next() in Node.js
... return next() is to ensure that the execution stops after triggering the callback.
If you don't do it, you risk triggering the callback a second time later, which usually has devastating results. Your code is fine as it is, but I would rewrite it as:
app.get('/users/:id?', function(req, res, next...
Rubymine: How to make Git ignore .idea files created by Rubymine
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That doesn't really work when the .idea folder is already under tracking
– ACV
Jan 28 '19 at 9:45
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How does the compilation/linking process work?
... #include directives with the content of the respective files (which is usually just declarations), doing replacement of macros (#define), and selecting different portions of text depending of #if, #ifdef and #ifndef directives.
The preprocessor works on a stream of preprocessing tokens. Macro subs...
what's the difference between “hadoop fs” shell commands and “hdfs dfs” shell commands?
...s dfs instead.
hdfs dfs <args>
same as 2nd i.e would work for all the operations related to HDFS and is the recommended command instead of hadoop dfs
below is the list categorized as hdfs commands.
namenode|secondarynamenode|datanode|dfs|dfsadmin|fsck|balancer|fetchdt|oiv|dfsgroups
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JavaScript OR (||) variable assignment explanation
...otcha' which is that the last one will always get assigned even if they're all undefined, null or false. Setting something you know isn't false, null, or undefined at the end of the chain is a good way to signal nothing was found.
– Erik Reppen
Aug 29 '11 at 1...
Simplest way to do a recursive self-join?
...e ultimate ancestors in your chain, change it as appropriate
UNION ALL
SELECT m.*
FROM mytable m
JOIN q
ON m.parentID = q.PersonID
)
SELECT *
FROM q
By adding the ordering condition, you can preserve the tree order:
WITH q AS
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