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How to export collection to CSV in MongoDB?
...=`mongo $dbname --eval "rs.slaveOk();db.getCollectionNames();"`;
collectionArray=($collections);
# for each collection
for ((i=0; i<${#collectionArray[@]}; ++i));
do
echo 'exporting collection' ${collectionArray[$i]}
# get comma separated list of keys. do this by peeking into the first d...
Make function wait until element exists
...r = new MutationObserver(function (mutations, me) {
// `mutations` is an array of mutations that occurred
// `me` is the MutationObserver instance
var canvas = document.getElementById('my-canvas');
if (canvas) {
handleCanvas(canvas);
me.disconnect(); // stop observing
return;
}...
Why should a Java class implement comparable?
... method is referred to as its natural
comparison method.
Lists (and arrays) of objects that
implement this interface can be sorted
automatically by Collections.sort (and
Arrays.sort). Objects that implement
this interface can be used as keys in
a sorted map or as elements in a
sor...
Removing multiple classes (jQuery)
...
Since jQuery 3.3.0, it is possible to pass arrays to .addClass(), .removeClass() and toggleClass(), which makes it easier if there is any logic which determines which classes should be added or removed, as you don't need to mess around with the space-delimited strings...
Best way to check if a URL is valid
...url($url) {
$path = parse_url($url, PHP_URL_PATH);
$encoded_path = array_map('urlencode', explode('/', $path));
$url = str_replace($path, implode('/', $encoded_path), $url);
return filter_var($url, FILTER_VALIDATE_URL) ? true : false;
}
// example
if(!validate_url("http://somedomai...
Fully custom validation error message with Rails
...z=>"can't be empty"}
#this returns the first element of the hash as an array like [:key,"value"]
@instance.errors.first # => [:song_rep_xyz, "can't be empty"]
#by doing the following, you are telling ruby to take just the second element of that array, which is the message.
@instance.errors.f...
pandas dataframe columns scaling with sklearn
...hod will produce the following warning:
DeprecationWarning: Passing 1d arrays as data is deprecated in 0.17
and will raise ValueError in 0.19. Reshape your data either using
X.reshape(-1, 1) if your data has a single feature or X.reshape(1, -1)
if it contains a single sample.
Converting ...
Using .NET, how can you find the mime type of a file based on the file signature not the extension
...nagedType.LPStr)] System.String pwzUrl,
[MarshalAs(UnmanagedType.LPArray)] byte[] pBuffer,
System.UInt32 cbSize,
[MarshalAs(UnmanagedType.LPStr)] System.String pwzMimeProposed,
System.UInt32 dwMimeFlags,
out System.UInt32 ppwzMimeOut,
System.UInt32 dwR...
Create a completed Task
...l() with no arguments. The MSDN documentation states that "If the supplied array/enumerable contains no tasks, the returned task will immediately transition to a RanToCompletion state before it's returned to the caller.". That sounds like what you want.
Update: I found the source over at Microsoft'...
Node.js - getting current filename
...
const scriptName = __filename.split(/[\\/]/).pop(); // Remove the last array element
console.log(scriptName);
// 'yourScript.js'
Don't Use This
You really should use path.basename instead (first documented in Node.js v0.1.25), because it handles all the corner cases you don't want to know abo...