大约有 40,000 项符合查询结果（耗时：0.0511秒） [XML]
Rails :dependent => :destroy VS :dependent => :delete_all
...te_all is made directly in your application and deletes by SQL :
DELETE * FROM users where compagny_id = XXXX
With the :destroy, there is an instantiation of all of your children. So, if you can't destroy it or if each has their own :dependent, its callbacks can be called.
...
Speed up the loop operation in R
... names.
So how better is it?
I run each function for data.frame with nrow from 1,000 to 10,000 by 1,000 and measure time with system.time
X <- as.data.frame(matrix(sample(1:10, n*9, TRUE), n, 9))
system.time(dayloop2(X))
Result is
You can see that your version depends exponentially from nr...
How to specify maven's distributionManagement organisation wide?
...arent pom file project (with packaging 'pom') generically for all projects from your organization.
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.or...
Android - Handle “Enter” in an EditText
...e answer (see starting with "You will want to..."). Second, this answer is from six years ago, and so one would presume that the OP's problem was solved. After all, the OP accepted the answer.
– CommonsWare
Oct 14 '15 at 21:30
...
When and why should I use fragments in Android applications? [duplicate]
...self the following questions:
Is the lifecycle of the fragment different from the activity's lifecycle?
If the lifecycle is different, you get better handling of the lifecycle using a fragment. For example, if you want to destroy the fragment, but not the activity. Such is the case, when you hav...
How to replace spaces in file names using a bash script
...ively replace spaces with underscores in file and directory names starting from a given root directory? For example:
18 Ans...
How do you determine the size of a file in C?
... You could probably change the return type to ssize_t and cast the size from an off_t without any trouble. It would seem to make more sense to use a ssize_t :-) (Not to be confused with size_t which is unsigned and cannot be used to indicate error.)
– Ted Percival
...
How do I make a textbox that only accepts numbers?
...mp; !char.IsControl(e.KeyChar);
}
NOTE: This DOES NOT prevent a user from Copy / Paste into this textbox. It's not a fail safe way to sanitize your data.
share
|
improve this answer
|...
Merge, update, and pull Git branches without using checkouts
...hat has 2 branches, A and B. I typically work on branch A, and merge stuff from branch B. For the merging, I would typically do:
...
Git merge errors
... 9-sign-in-out
# Create a merge commit, which looks as if it's merging in from master, but is
# actually discarding everything from the master branch and keeping everything
# from 9-sign-in-out:
git merge -s ours master
# Switch back to the master branch:
git checkout master
# Merge the topic bra...