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How to avoid 'cannot read property of undefined' errors?
...tive "in", but allows paths.
var testObject = {a: {b: {c: 'walrus'}}};
if(_.has(testObject, 'a.b.c')) {
//Safely access your walrus here
}
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Getting the SQL from a Django QuerySet [duplicate]
...et = MyModel.objects.all()
>>> print(queryset.query)
SELECT "myapp_mymodel"."id", ... FROM "myapp_mymodel"
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Java ByteBuffer to String
...sibling getBytes() method:
byte[] bytes = k.getBytes( StandardCharsets.UTF_8 );
To put bytes with a particular encoding into a String, you can use a different String constructor:
String v = new String( bytes, StandardCharsets.UTF_8 );
Note that ByteBuffer.array() is an optional operation. If y...
Error handling with node.js streams
...eam module
instantiate ( or inherit from) the Transform class
implement a _transform method which takes a (chunk, encoding, callback).
The chunk is your data. Most of the time you won't need to worry about encoding if you are working in objectMode = true. The callback is called when you are done...
Accessing private member variables from prototype-defined functions
...ns they're going to be public. So we just stick to naming conventions for _private fields.
Don't bother mixing Closures with Prototypes
I think you shouldn't mix closure variables with prototype methods. You should use one or the other.
When you use a closure to access a private variable, pro...
How to import CSV file data into a PostgreSQL table?
...rticle.
Solution paraphrased here:
Create your table:
CREATE TABLE zip_codes
(ZIP char(5), LATITUDE double precision, LONGITUDE double precision,
CITY varchar, STATE char(2), COUNTY varchar, ZIP_CLASS varchar);
Copy data from your CSV file to the table:
COPY zip_codes FROM '/path/to/csv/ZI...
What does `m_` variable prefix mean?
I often see m_ prefix used for variables ( m_World , m_Sprites ,...) in tutorials, examples and other code mainly related to game development.
...
When and why will a compiler initialise memory to 0xCD, 0xDD, etc. on malloc/free/new/delete?
...oc().
0xBAADF00D Bad Food Memory allocated by LocalAlloc() with LMEM_FIXED,but
not yet written to.
0xFEEEFEEE OS fill heap memory, which was marked for usage,
but wasn't allocated by HeapAlloc() or LocalAlloc().
...
Preserving order with LINQ
...
so because OrderBy is a stable sort, then: seq.OrderBy( _ => _.Key ) will put the elements in to exactly the same order as seq.GroupBy( _ => _.Key ).SelectMany( _ => _ ). Is that correct?
– dmg
Feb 1 '16 at 22:11
...
Get names of all keys in the collection
...You could do this with MapReduce:
mr = db.runCommand({
"mapreduce" : "my_collection",
"map" : function() {
for (var key in this) { emit(key, null); }
},
"reduce" : function(key, stuff) { return null; },
"out": "my_collection" + "_keys"
})
Then run distinct on the resulting collecti...