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How do I revert a Git repository to a previous commit?
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This depends a lot on what you mean by "revert".
Temporarily switch to a different commit
If you want to temporarily go back to it, fool around, then come back to where you are, all you have to do is check out the desired commit:
# This will detach your HEAD, that is, leave you with no branch check...
Where is Java's Array indexOf?
...e are a couple of ways to accomplish this using the Arrays utility class.
If the array is not sorted and is not an array of primitives:
java.util.Arrays.asList(theArray).indexOf(o)
If the array is primitives and not sorted, one should use a solution offered by one of the other answers such as Ke...
How can I check if multiplying two numbers in Java will cause an overflow?
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If a and b are both positive then you can use:
if (a != 0 && b > Long.MAX_VALUE / a) {
// Overflow
}
If you need to deal with both positive and negative numbers then it's more complicated:
long maximum = Lo...
Is there a simple way to delete a list element by value?
I want to remove a value from a list if it exists in the list (which it may not).
21 Answers
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Fragment onCreateView and onActivityCreated called twice
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public void onTabSelected(Tab tab, FragmentTransaction ft) {
if (mFragment == null) {
mFragment = Fragment.instantiate(mActivity, mClass.getName());
ft.replace(android.R.id.content, mFragment, mTag);
} else {
if (mFragment.isDetached()) {
...
How can I use optional parameters in a T-SQL stored procedure?
... creating a stored procedure to do a search through a table. I have many different search fields, all of which are optional. Is there a way to create a stored procedure that will handle this? Let's say I have a table with four fields: ID, FirstName, LastName and Title. I could do something like...
How to cast an Object to an int
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If you're sure that this object is an Integer :
int i = (Integer) object;
Or, starting from Java 7, you can equivalently write:
int i = (int) object;
Beware, it can throw a ClassCastException if your object isn't an Int...
Java: Detect duplicates in ArrayList?
...into a Set (using the Set(Collection) constructor or Set.addAll), then see if the Set has the same size as the ArrayList.
List<Integer> list = ...;
Set<Integer> set = new HashSet<Integer>(list);
if(set.size() < list.size()){
/* There are duplicates */
}
Update: If I'm un...
How can I print variable and string on same line in Python?
I am using python to work out how many children would be born in 5 years if a child was born every 7 seconds. The problem is on my last line. How do I get a variable to work when I'm printing text either side of it?
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Javascript shorthand ternary operator
...ber || 1;
Something like that what you're looking for, where it defaults if undefined?
var foo = bar || 1; // 1
var bar = 2;
foo = bar || 1; // 2
By the way, this works for a lot of scenarios, including objects:
var foo = bar || {}; // secure an object is assigned when bar is absent
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