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How to make HTML input tag only accept numerical values?
I need to make sure that a certain <input> field only takes numbers as value.
The input is not part of a form. Hence it doesn't get submitted, so validating during submission is not an option. I want the user to be unable to type in any characters other than numbers.
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Get keys from HashMap in Java
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If you want to store all keys in array list : List<String> keys = new ArrayList<>(mLoginMap.keySet());
– Pratik Butani
Dec 24 '18 at 6:42
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How can I check the size of a collection within a Django template?
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See https://docs.djangoproject.com/en/stable/ref/templates/builtins/#if : just use, to reproduce their example:
{% if athlete_list %}
Number of athletes: {{ athlete_list|length }}
{% else %}
No athletes.
{% endif %}
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A generic list of anonymous class
...bly as an extension method). Another example might be:
public static List<T> CreateList<T>(params T[] elements)
{
return new List<T>(elements);
}
var list = CreateList(o, o1);
You get the idea :)
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Pass a data.frame column name to a function
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You can just use the column name directly:
df <- data.frame(A=1:10, B=2:11, C=3:12)
fun1 <- function(x, column){
max(x[,column])
}
fun1(df, "B")
fun1(df, c("B","A"))
There's no need to use substitute, eval, etc.
You can even pass the desired function as a param...
How to handle dependency injection in a WPF/MVVM application
...rolViewModel UserControlViewModel
{
get { return IocKernel.Get<UserControlViewModel>();} // Loading UserControlViewModel will automatically load the binding for IStorage
}
}
Make the ViewModelLocator an application wide resource in App.xaml:
<Application ...>
<A...
Select first 4 rows of a data.frame in R
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Use head:
dnow <- data.frame(x=rnorm(100), y=runif(100))
head(dnow,4) ## default is 6
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How to get a tab character?
...e by HTML parsers and collapsed into a single space except those within a <pre> block, where literal tabs will be rendered as 8 spaces in a monospace font.
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get dictionary value by key
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Why not just use key name on dictionary, C# has this:
Dictionary<string, string> dict = new Dictionary<string, string>();
dict.Add("UserID", "test");
string userIDFromDictionaryByKey = dict["UserID"];
If you look at the tip suggestion:
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Modern way to filter STL container?
...after years of C# I was wondering what the modern - read: C++11 - way of filtering an array would be, i.e. how can we achieve something similar to this Linq query:
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