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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...
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...
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
...
C++ Redefinition Header Files (winsock2.h)
...list that <windows.h> is included after <winsock2.h> or define _WINSOCKAPI_ first:
#define _WINSOCKAPI_ // stops windows.h including winsock.h
#include <windows.h>
// ...
#include "MyClass.h" // Which includes <winsock2.h>
See also this.
...
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().
...
Is it better in C++ to pass by value or pass by constant reference?
...r iterators and for function objects (lambdas, classes deriving from std::*_function).
This was especially true before the existence of move semantics. The reason is simple: if you passed by value, a copy of the object had to be made and, except for very small objects, this is always more expensive...
Get Android API level of phone currently running my application [duplicate]
...g the API level would be to check the value of android.os.Build.VERSION.SDK_INT, which is an integer.
In either case, the integer you get maps to an enum value from all those defined in android.os.Build.VERSION_CODES:
SDK_INT value Build.VERSION_CODES Human Version Name
1 ...
When would anyone use a union? Is it a remnant from the C-only days?
...For example, let's say you want to create your own Variant type:
struct my_variant_t {
int type;
union {
char char_value;
short short_value;
int int_value;
long long_value;
float float_value;
double double_value;
void* ptr_value;
}...
Example of multipart/form-data
...0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Cookie: __atuvc=34%7C7; permanent=0; _gitlab_session=226ad8a0be43681acf38c2fab9497240; __profilin=p%3Dt; request_method=GET
Connection: keep-alive
Content-Type: multipart/form-data; boundary=---------------------------905191404154484...
What exactly does an #if 0 … #endif block do?
...entire thing. And the #if 0s will nest with each other, like so:
#if 0
pre_foo();
#if 0
foo();
bar(x, y); /* x must not be NULL */
baz();
#endif
quux();
#endif
Although of course this can get a bit confusing and become a maintenance headache if not commented properly.
...