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In Firebase, is there a way to get the number of children of a node without loading all the node dat
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The code snippet you gave does indeed load the entire set of data and then counts it client-side, which can be very slow for large amounts of data.
Firebase doesn't currently have a way to count children without loading data, but we do plan to add it.
For now, one solution wou...
When do I need to use AtomicBoolean in Java?
...e. You can fix it by using AtomicBoolean:
if (atomicInitialized.compareAndSet(false, true)) {
initialize();
}
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How many concurrent AJAX (XmlHttpRequest) requests are allowed in popular browsers?
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@DaveLawrence I just checked and the full data set seems to contain Chrome 60 and 61 which is pretty up to date.
– Simon East
Jul 20 '17 at 7:06
ad...
Cost of len() function
...al length of the element - very fast) on every type you've mentioned, plus set and others such as array.array.
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Entity Framework - Add Navigation Property Manually
... what you do:
1 - Right click on the designer, Add -> Association
2 - Setup the association and cardinalities (People *..1 Gender, People *..1 Race)
3 - Go into the Model Browser -> Associations
4 - Right click on your newly created associations, click Properties
5 - Here you need to setu...
How to read if a checkbox is checked in PHP?
...value="value1">
After submitting the form you can check it with:
isset($_POST['test'])
or
if ($_POST['test'] == 'value1') ...
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Include intermediary (through model) in responses in Django Rest Framework
...fine a field on it like:
groups = MembershipSerializer(source='membership_set', many=True)
and then on your membership serializer you can create this:
class MembershipSerializer(serializers.HyperlinkedModelSerializer):
id = serializers.Field(source='group.id')
name = serializers.Field(s...
What's the best way to retry an AJAX request on failure using jQuery?
... console.log(retries); // prrint retry count
retries > 0 && setTimeout(function(){
runAjax(--retries);
},delay);
})
})(3, 100);
Another approach would be to use a retries property on the $.ajax
// define ajax settings
var ajaxSettings = {
type : 'GET',
url ...
How do I find numeric columns in Pandas?
...Following codes will return list of names of the numeric columns of a data set.
cnames=list(marketing_train.select_dtypes(exclude=['object']).columns)
here marketing_train is my data set and select_dtypes() is function to select data types using exclude and include arguments and columns is used t...
How can I count all the lines of code in a directory recursively?
...wc -l **/*.php
In the Bash shell this requires the globstar option to be set, otherwise the ** glob-operator is not recursive. To enable this setting, issue
shopt -s globstar
To make this permanent, add it to one of the initialization files (~/.bashrc, ~/.bash_profile etc.).
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