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Check that Field Exists with MongoDB
So I'm attempting to find all records who have a field set and isn't null.
4 Answers
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What is the difference between Scala's case class and class?
...xclusively depend on their constructor arguments.
This functional concept allows us to
use a compact initialization syntax (Node(1, Leaf(2), None)))
decompose them using pattern matching
have equality comparisons implicitly defined
In combination with inheritance, case classes are used to mimi...
Create Generic method constraining T to an Enum
... You don't gain much by including the other interfaces because almost all of the built-in value types implement all of those interfaces. This is especially true for constraints on a generic extension method, which is extremely handy for operating on enums, except for the fact that those extensi...
WPF ToolBar: how to remove grip and overflow
...right. they are both grayed out, but we'd like them to not be displayed at all.
6 Answers
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UITextField text change event
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From proper way to do uitextfield text change call back:
I catch the characters sent to a UITextField control something like this:
// Add a "textFieldDidChange" notification method to the text field control.
In Objective-C:
[textField addTarget:self
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What do people find difficult about C pointers? [closed]
...duling, actual CPU operations, or assembly-level memory management isn't really required.
When I was teaching, I found the following holes in students' understanding to be the most common source of problems:
Heap vs Stack storage. It is simply stunning how many people do not understand this, even...
Multiple line code example in Javadoc comment
I have a small code example I want to include in the Javadoc comment for a method.
15 Answers
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How can I get query string values in JavaScript?
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For a querystring of ?mykey=0&m.+key=1, calling getParameterByName("m.+key") would return 0 instead of 1. You need to escape the regular expression metacharacters in name before building your regular expression. And you only need to call .replace() once by using t...
Bash foreach loop
... input runs the cat program with the input lines as argument(s).
If you really want to do this in a loop, you can:
for fn in `cat filenames.txt`; do
echo "the next file is $fn"
cat $fn
done
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What's the difference between a catalog and a schema in a relational database?
...l point of view :
The catalog is the place where--among other things--all of the various schemas (external, conceptual, internal) and all of the corresponding mappings (external/conceptual, conceptual/internal) are kept.
In other words, the catalog contains detailed information (sometimes...