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Return positions of a regex match() in Javascript?
...parsed. In addition, it has an index
property, which represents the zero-based index of the match in the
string.
When dealing with a non-global regex (i.e., no g flag on your regex), the value returned by .match() has an index property...all you have to do is access it.
var index = str.match(...
Why do most C developers use define instead of const? [duplicate]
...the preprocessor: you can use it with #ifdef to do conditional compilation based on its value, or use the stringizing operator # to get a string with its value. And as the compiler knows its value at compile time it may optimize code based on that value.
For example:
#define SCALE 1
...
scaled_x...
Aggregate / summarize multiple variables per group (e.g. sum, mean)
...('.*[0-9]')), sum)
# summarising a specific set of non-grouping variables based on condition (class)
df2 <- df1 %>% group_by(year, month) %>% summarise_if(is.numeric, sum)
The result of the latter two options:
year month x1 x2
<dbl> <dbl> <dbl>...
Remove rows with all or some NAs (missing values) in data.frame
...ata.frame does not support cols=.
Benchmark result
Here is a comparison of base (blue), dplyr (pink), and data.table (yellow) methods for dropping either all or select missing observations, on notional dataset of 1 million observations of 20 numeric variables with independent 5% likelihood of being ...
Why does range(start, end) not include end?
...lements which equals len(range(0, 10)). Remember that programmers prefer 0-based indexing.
Also, consider the following common code snippet:
for i in range(len(li)):
pass
Could you see that if range() went up to exactly len(li) that this would be problematic? The programmer would need to exp...
Set “Homepage” in Asp.Net MVC
...tion defined in the MapRoute method when/if they navigate to your site’s base URL, i.e., yoursite.com will route users to yoursite.com/foo/index:
app.UseMvc(routes =>
{
routes.MapRoute(
name: "default",
template: "{controller=FooController}/{action=Index}/{id?}");
});
Pre-ASP.NET Co...
File input 'accept' attribute - is it useful?
... a hundred different file types.
Usage
Note: These examples were written based on the current specification and may not actually work in all (or any) browsers. The specification may also change in the future, which could break these examples.
h1 { font-size: 1em; margin:1em 0; }
h1 ~ h1 { bo...
How can I override Bootstrap CSS styles?
...should not effect the load time much since you are overriding parts of the base stylesheet.
Here are some best practices I personally follow:
Always load custom CSS after the base CSS file (not responsive).
Avoid using !important if possible. That can override some important styles from the base ...
How to get a JavaScript object's class?
...etClass() in JavaScript. Mostly that's due to JavaScript being a prototype-based language, as opposed to Java being a class-based one.
Depending on what you need getClass() for, there are several options in JavaScript:
typeof
instanceof
obj.constructor
func.prototype, proto.isPrototypeOf
A few...
What is the difference between JSON and Object Literal Notation?
...ion .json.
► JavaScript Object Notation (JSON) is a lightweight, text-based, language-independent data interchange format. JSON has been used to exchange data between applications written in any Programming language.
The JSON object is a single object that contains two functions, parse and ...