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Get keys from HashMap in Java
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A HashMap contains more than one key. You can use keySet() to get the set of all keys.
team1.put("foo", 1);
team1.put("bar", 2);
will store 1 with key "foo" and 2 with key "bar". To iterate over all the keys:
for ( String key : team1.keySet() ) {
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Why is my git repository so big?
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I recently pulled the wrong remote repository into the local one (git remote add ... and git remote update). After deleting the unwanted remote ref, branches and tags I still had 1.4GB (!) of wasted space in my repository. I was only able to get rid of this by cloning it with git clo...
Rename multiple files based on pattern in Unix
...re are several ways, but using rename will probably be the easiest.
Using one version of rename:
rename 's/^fgh/jkl/' fgh*
Using another version of rename (same as Judy2K's answer):
rename fgh jkl fgh*
You should check your platform's man page to see which of the above applies.
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Understanding Spliterator, Collector and Stream in Java 8
...lit off part of the collection, e.g. because you're parallelizing and want one thread to work on one part of the collection, one thread to work on another part, etc.
You should essentially never be saving values of type Stream to a variable, either. Stream is sort of like an Iterator, in that it's...
Delete column from pandas DataFrame
...1', 'Col2', ...]
df.drop(columns, inplace=True, axis=1)
This will delete one or more columns in-place. Note that inplace=True was added in pandas v0.13 and won't work on older versions. You'd have to assign the result back in that case:
df = df.drop(columns, axis=1)
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What is the effect of extern “C” in C++?
...s are distinct types even if otherwise identical
Linkage specs nest, inner one determines the final linkage
extern "C" is ignored for class members
At most one function with a particular name can have "C" linkage (regardless of namespace)
extern "C" forces a function to have external linkage (cannot...
How do I find the most recent git commit that modified a file?
...all it like this:
git log my/file.c
If you really only want to list the one most recent commit, for example to use it in a script, use the -n 1 option:
git log -n 1 --pretty=format:%H -- my/file.c
--pretty=format:%h tells git log to show only the commit hash. The -- separater stops the file na...
ActiveRecord: size vs count
...f you're dealing with more complex queries is there any advantage to using one method over the other? How are they different?
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Forking vs. Branching in GitHub
... collaborator for that specific project.
Forking is nothing more than a clone on the GitHub server side:
without the possibility to directly push back
with fork queue feature added to manage the merge request
You keep a fork in sync with the original project by:
adding the original project as...
Preventing Laravel adding multiple records to a pivot table
...resence of an existing record by writing a very simple condition like this one :
if (! $cart->items->contains($newItem->id)) {
$cart->items()->save($newItem);
}
Or/and you can add unicity condition in your database, it would throw an exception during an attempt of saving a doub...