大约有 40,000 项符合查询结果（耗时：0.0249秒） [XML]
What's an elegant way to conditionally add a class to an HTML element in a view?
...sses where the boolean value evaluated to true.
Sample Usage
class_names(foo: true, bar: false, baz: some_truthy_variable)
# => "foo baz"
Other Use Cases
This helper can be used within ERB tags or with Rails helpers such as link_to.
<div class="<%= class_string(ok: @success) %>">...
How do I check for nulls in an '==' operator overload without infinite recursion?
...ccepted answer is a function, that executes the == of object. This is basically the same as the accepted answer, with one downside: It needs a cast. The accpeted answer is thus superior.
– Mafii
Jul 8 '16 at 12:43
...
How do you check in python whether a string contains only numbers?
....isdigit():
From the isdigit documentation:
str.isdigit()
Return True if all characters in the string are digits and there is at least one character, False otherwise. Digits include decimal characters and digits that need special handling, such as the compatibility superscript digits. This covers ...
C# generic type constraint for everything nullable
...vs. the unhandiness of exceptions in a static constructor. Since you're really implementing a poor-mans static analyzer here, this exception should never be thrown except during development. Finally, even if you want to avoid static construction exceptions at all costs (unwise), then you should sti...
Repeat string to certain length
... that need to be // in Python 3? Or dropping the +1 and using an explicit call to a ceiling function would suffice. Also, a note: the string generated actually has an extra repetition when it divides evenly; the extra gets cut off by the splice. That confused me at first.
– jpm...
Why does Python code run faster in a function?
...e names are assigned to indexes. This is possible because you can't dynamically add local variables to a function. Then retrieving a local variable is literally a pointer lookup into the list and a refcount increase on the PyObject which is trivial.
Contrast this to a global lookup (LOAD_GLOBAL), w...
How to Batch Rename Files in a macOS Terminal?
...g).
If you find yourself batch-renaming files frequently, consider installing a specialized tool such as the Perl-based rename utility.
On macOS you can install it using popular package manager Homebrew as follows:
brew install rename
Here's the equivalent of the command at the top using rena...
The easiest way to transform collection to array?
...nt context) way to transform it to Foo[] ? Any well-known libraries are allowed.
8 Answers
...
Rename multiple files by replacing a particular pattern in the filenames using a shell script [dupli
...ho "$f" | sed s/IMG/VACATION/)"; done
In this example, I am assuming that all your image files contain the string IMG and you want to replace IMG with VACATION.
The shell automatically evaluates *.jpg to all the matching files.
The second argument of mv (the new name of the file) is the output of t...
Regular expression to match URLs in Java
...s.
*/
public class Patterns {
/**
* Regular expression to match all IANA top-level domains.
* List accurate as of 2011/07/18. List taken from:
* http://data.iana.org/TLD/tlds-alpha-by-domain.txt
* This pattern is auto-generated by frameworks/ex/common/tools/make-iana-tl...