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How to check if a map contains a key in Go?
...thout worrying about the actual
value, you can use the blank identifier (_) in place of the usual
variable for the value.
_, present := timeZone[tz]
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Add Foreign Key to existing table
...
To add a foreign key (grade_id) to an existing table (users), follow the following steps:
ALTER TABLE users ADD grade_id SMALLINT UNSIGNED NOT NULL DEFAULT 0;
ALTER TABLE users ADD CONSTRAINT fk_grade_id FOREIGN KEY (grade_id) REFERENCES grades(id);
...
Can I find events bound on an element with jQuery?
...
In modern versions of jQuery, you would use the $._data method to find any events attached by jQuery to the element in question. Note, this is an internal-use only method:
// Bind up a couple of event handlers
$("#foo").on({
click: function(){ alert("Hello") },
mous...
Is it ok to use dashes in Python files when trying to import them?
...o import a file with a dash in its name, you can do the following::
python_code = __import__('python-code')
But, as also mentioned above, this is not really recommended. You should change the filename if it's something you control.
...
python assert with and without parenthesis
...a convenient way to insert debugging assertions into a program:
assert_stmt ::= "assert" expression ["," expression]
The simple form, assert expression, is equivalent to
if __debug__:
if not expression: raise AssertionError
The extended form, assert expression1, expression2, is equi...
How do I convert a Vector of bytes (u8) to a string
...string slice (assuming a UTF-8 encoding):
use std::str;
//
// pub fn from_utf8(v: &[u8]) -> Result<&str, Utf8Error>
//
// Assuming buf: &[u8]
//
fn main() {
let buf = &[0x41u8, 0x41u8, 0x42u8];
let s = match str::from_utf8(buf) {
Ok(v) => v,
E...
Algorithm to detect overlapping periods [duplicate]
... throw new Exception("Invalid range edges.");
}
_Start = start;
_End = end;
}
#endregion
#region Properties
private DateTime _Start;
public DateTime Start {
get { return _Start; }
private set { _Start = value; }
}
priva...
MongoDB SELECT COUNT GROUP BY
...ier way to do it using aggregate:
db.contest.aggregate([
{"$group" : {_id:"$province", count:{$sum:1}}}
])
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Some built-in to pad a list in python
...
a += [''] * (N - len(a))
or if you don't want to change a in place
new_a = a + [''] * (N - len(a))
you can always create a subclass of list and call the method whatever you please
class MyList(list):
def ljust(self, n, fillvalue=''):
return self + [fillvalue] * (n - len(self))
a...
Unioning two tables with different number of columns
...in column orders. this example below produces an error:
create table test1_1790 (
col_a varchar2(30),
col_b number,
col_c date);
create table test2_1790 (
col_a varchar2(30),
col_c date,
col_b number);
select * from test1_1790
union all
select * from test2_1790;
ORA-01790: expression must have ...