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What is a NullReferenceException, and how do I fix it?
...ess members (such as methods) through a null reference. The simplest case:
string foo = null;
foo.ToUpper();
This will throw a NullReferenceException at the second line because you can't call the instance method ToUpper() on a string reference pointing to null.
Debugging
How do you find the source ...
How to add an object to an array
... aData) {
alert(aData[i].fullname());
}
/* convert array of object into string json */
var jsonString = JSON.stringify(aData);
document.write(jsonString);
Push object into array
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imp...
Curly braces in string in PHP
What is the meaning of { } (curly braces) in string literals in PHP?
5 Answers
5
...
Rails Root directory path?
... 3 and newer:
Rails.root
which returns a Pathname object. If you want a string you have to add .to_s. If you want another path in your Rails app, you can use join like this:
Rails.root.join('app', 'assets', 'images', 'logo.png')
In Rails 2 you can use the RAILS_ROOT constant, which is a string...
ReSharper warns: “Static field in generic type”
...public class Test
{
public static void Main()
{
Generic<string>.Foo = 20;
Generic<object>.Foo = 10;
Console.WriteLine(Generic<string>.Foo); // 20
}
}
As you can see, Generic<string>.Foo is a different field from Generic<object>.Foo ...
Read Excel File in Python
....
You mentioned in the question that you also want the values output to a string. I dynamically build a format string for the output from the FORMAT column list. Rows are appended to the values string separated by a new line char.
The output column order is determined by the order of the column na...
Resolving a Git conflict with binary files
...intuitive - something like git resolve would be nice, but would also be an extra step ...
– VolkA
Nov 10 '08 at 20:22
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Which characters make a URL invalid?
...
Here's a regex that will determine if the entire string contains only the characters above: /^[!#$&-;=?-[]_a-z~]+$/
– Leif Wickland
Oct 7 '11 at 17:01
...
What is the relative performance difference of if/else versus switch statement in Java?
... First create some interface:
public interface Action {
void execute(String input);
}
And get hold of all implementations in some Map. You can do this either statically or dynamically:
Map<String, Action> actions = new HashMap<String, Action>();
Finally replace the if/else or ...
Determine the type of an object?
...t question, don't use type - use isinstance:
def foo(obj):
"""given a string with items separated by spaces,
or a list or tuple,
do something sensible
"""
if isinstance(obj, str):
obj = str.split()
return _foo_handles_only_lists_or_tuples(obj)
This covers the cas...