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Why does String.valueOf(null) throw a NullPointerException?
...ar[]) overload is chosen in this case.
String.valueOf(char[]) expects the array to be non-null, and since null is given in this case, it then throws NullPointerException.
The easy "fix" is to cast the null explicitly to Object as follows:
System.out.println(String.valueOf((Object) null));
// prin...
Aren't promises just callbacks?
...pi(), api2(), api3()]).then(function(result) {
//do work. result is an array contains the values of the three fulfilled promises.
}).catch(function(error) {
//handle the error. At least one of the promises rejected.
});
Hope you see Promises in a new light now.
...
Java: Best way to iterate through a Collection (here ArrayList)
...lement as well. This is basically equivalent to the other two variants for ArrayLists, but will be really slow if you use a LinkedList.
The second one is useful when you don't need the index of the element but might need to remove the elements as you iterate. But this has the disadvantage of being ...
Why are trailing commas allowed in a list?
...
It's a common syntactical convention to allow trailing commas in an array, languages like C and Java allow it, and Python seems to have adopted this convention for its list data structure. It's particularly useful when generating code for populating a list: just generate a sequence of element...
What's the canonical way to check for type in Python?
...hich is given. In my code I often cannot know if I recieve an object or an array of objects, and I use type-checking internally to convert a single object to a one-element list.
– sastanin
Jan 12 '09 at 11:21
...
Changes in import statement python3
... fact, functions don't even use a dict for local storage, but an optimized array where variables get unique indices.
– Veky
Sep 24 '15 at 11:06
add a comment
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What are the differences between “generic” types in C++ and Java?
...s like have int parameters in template definitions that determine sizes of arrays and such.
Java doesn't work like that. In Java all objects extent from java.lang.Object so, pre-Generics, you'd write code like this:
public class PhoneNumbers {
private Map phoneNumbers = new HashMap();
public...
How to pass argument to Makefile from command line?
...ment called on the command line. Instead, I assign MAKECMDGOALS to a shell array and then remove the first element: @ args=($(MAKECMDGOALS)); args=("$${args[@]:1}")
– Gingi
Aug 4 '15 at 16:18
...
What are the advantages of using a schema-free database like MongoDB compared to a relational databa
...naries, Ruby hashes, etc. This is a rich data structure capable of holding arrays and other documents. This means you can often represent in a single entity a construct that would require several tables to properly represent in a relational db. This is especially useful if your data is immutable.
De...
Handling very large numbers in Python
...er factoring operation which is much more expensive than just accessing an array.
Adding cards would be multiplication, and removing cards division, both of large multi-word numbers, which are more expensive operations than adding or removing elements from lists.
The actual numeric value of a hand w...