大约有 40,000 项符合查询结果（耗时：0.0477秒） [XML]
Why no love for SQL? [closed]
... bad to make an abstraction layer valuable.
If you're doing a very simple script or application, you can afford to mix SQL calls in your code wherever you like. However, if you're doing a complex system, isolating the database calls in separate module(s) is a good practice and so it is isolating yo...
Make a Bash alias that takes a parameter?
...reate a function.
alias does not accept parameters but a function can be called just like an alias. For example:
myfunction() {
#do things with parameters like $1 such as
mv "$1" "$1.bak"
cp "$2" "$1"
}
myfunction old.conf new.conf #calls `myfunction`
By the way, Bash functions def...
How to create a MySQL hierarchical recursive query
... parent_id
from products
where parent_id = 19
union all
select p.id,
p.name,
p.parent_id
from products p
inner join cte
on p.parent_id = cte.id
)
select * from cte;
The value specified in parent_id = 19 should be set to the...
MongoDB atomic “findOrCreate”: findOne, insert if nonexistent, but do not update
as the title says, I want to perform a find (one) for a document, by _id, and if doesn't exist, have it created, then whether it was found or was created, have it returned in the callback.
...
How to parse JSON in Scala using standard Scala classes?
... {
"languages": [{
"name": "English",
"is_active": true,
"completeness": 2.5
}, {
"name": "Latin",
"is_active": false,
"completeness": 0.9
}]
}
""".stripMargin
val result = for {
Some(M(m...
How can I check if a jQuery plugin is loaded?
...de
}
dateJs however is not a jQuery plugin. It modifies/extends the javascript date object, and is not added as a jQuery namespace. You could check if the method you need exists, for example:
if(Date.today) {
//Use the dateJS today() method
}
But you might run into problems where the A...
List of Big-O for PHP functions
After using PHP for a while now, I've noticed that not all built-in PHP functions are as fast as expected. Consider these two possible implementations of a function that finds if a number is prime using a cached array of primes.
...
Remove a character from the end of a variable
...
Use target=${1%/}
See this the parameter substitution of this bash scripting guide for more.
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Circle drawing with SVG's arc path
...plicity is the main advantage over the multiple-arc-path method (e.g. when scripting you only plug in one value and you're done for any arc length)
The arc starts at the rightmost point, and can be shifted around using a rotate transform.
Note: Firefox has an odd bug where rotations over 90 degree...
Convert unix time to readable date in pandas dataframe
...12.15
3 1349979305 12.19
4 1350065705 12.15
In [25]: df['date'] = pd.to_datetime(df['date'],unit='s')
In [26]: df.head()
Out[26]:
date price
0 2012-10-08 18:15:05 12.08
1 2012-10-09 18:15:05 12.35
2 2012-10-10 18:15:05 12.15
3 2012-10-11 18:15:05 12.19
4 2012-10-12 18:15:...