大约有 43,000 项符合查询结果（耗时：0.0622秒） [XML]
How to set DOM element as the first child?
I have element E and I'm appending some elements to it. All of a sudden, I find out that the next element should be the first child of E. What's the trick, how to do it? Method unshift doesn't work because E is an object, not array.
...
Adding a column to an existing table in a Rails migration
...ontaining line:
add_column :users, email, string
Then do a rake db:migrate and it'll run the new migration, creating the new column.
If you have not yet run the original migration you can just edit it, like you're trying to do. Your migration code is almost perfect: you just need to remove the add_...
How to get “wc -l” to print just the number of lines without file name?
outputs number of lines and file name.
9 Answers
9
...
How can I remove all my changes in my SVN working directory?
I have an SVN working directory. I made some changes in that directory, and it shows in svn status . But is there any way for me to remove all my changes in there and just get everything from the trunk using the command line?
...
Converting from a string to boolean in Python?
...ref.html#distutils.util.strtobool
True values are y, yes, t, true, on and 1; false values are n, no, f, false, off and 0. Raises ValueError if val is anything else.
Be aware that distutils.util.strtobool() returns integer representations and thus it needs to be wrapped with bool() to get Bool...
How to check if object has any properties in JavaScript?
...ws:
for(var prop in ad) {
if (ad.hasOwnProperty(prop)) {
// handle prop as required
}
}
It is important to use the hasOwnProperty() method, to determine whether the object has the specified property as a direct property, and not inherited from the object's prototype chain.
Edit
...
Why is “if not someobj:” better than “if someobj == None:” in Python?
... the object has a __nonzero__ special method (as do numeric built-ins, int and float), it calls this method. It must either return a bool value which is then directly used, or an int value that is considered False if equal to zero.
Otherwise, if the object has a __len__ special method (as do contain...
When to use os.name, sys.platform, or platform.system?
...
Dived a bit into the source code.
The output of sys.platform and os.name are determined at compile time. platform.system() determines the system type at run time.
sys.platform is specified as a compiler define during the build configuration.
os.name checks whether certain os specific...
What is scaffolding? Is it a term for a particular platform?
... to
generate code that the application can
use to create, read, update and delete
database entries, effectively treating
the template as a "scaffold" on which
to build a more powerful application.
share
|...
Chrome Dev Tools - “Size” vs “Content”
...in the Network tab of Chrome's dev tools, one column specifies both "size" and "content":
4 Answers
...