大约有 44,000 项符合查询结果（耗时：0.0543秒） [XML]
How to search in array of object in mongodb
...hout $elemMatch mongo will look for users with National Medal in some year and some award in 1975s, but not for users with National Medal in 1975.
See MongoDB $elemMatch Documentation for more info. See Read Operations Documentation for more information about querying documents with arrays.
...
What is the difference between print and puts?
For example in this line of code I wrote, print and puts produce different results.
6 Answers
...
input type=“submit” Vs button tag are they interchangeable?
input type="submit" and button tag are they interchangeable? or if there is any difference then When to use input type="submit" and when button ?
...
How does Rails keep track of which migrations have run for a database?
...runs a migration, it takes the leading digits in the migration's file name and inserts a row for that "version", indicating it has been run. If you roll back that migration, Rails will delete the corresponding row from schema_migrations.
For example, running a migration file named 20120620193144_cr...
Is it safe to resolve a promise multiple times?
...
As I understand promises at present, this should be 100% fine. Only thing to understand is that once resolved (or rejected), that is it for a defered object - it is done.
If you should call then(...) on it's promise again, you should i...
How do I concatenate two strings in C?
...e that the function returns a block of heap allocated memory to the caller and passes on ownership of that memory. It is the responsibility of the caller to free the memory when it is no longer needed.
Call the function like this:
char* s = concat("derp", "herp");
// do things with s
free(s); // d...
Disable sorting for a particular column in jQuery DataTables
...argets': [ -1 ], for second 'aTargets': [ 1 ], for third 'aTargets': [ 2 ] and so on.
– Lasang
Mar 20 '13 at 7:19
5
...
How is this fibonacci-function memoized?
...mechanism in Haskell is by-need: when a value is needed, it is calculated, and kept ready in case it is asked for again. If we define some list, xs=[0..] and later ask for its 100th element, xs!!99, the 100th slot in the list gets "fleshed out", holding the number 99 now, ready for next access.
Th...
NSUserDefaults - How to tell if a key exists
I'm working on a small iPhone app, and I am using NSUserDefaults as my data persistence. It only has to keep track of a few things, such as some names and some numbers so I figure I might as well keep it simple.
...
detect key press in python?
I am making a stopwatch type program in python and I would like to know how to detect if a key is pressed (such as p for pause and s for stop), and I would not like it to be something like raw_input that waits for the user's input before continuing execution. Anyone know how to do this in a while lo...