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Get keys from HashMap in Java
...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() ) {
System.out.println( key );
}
will print "foo"...
How do I use itertools.groupby()?
I haven't been able to find an understandable explanation of how to actually use Python's itertools.groupby() function. What I'm trying to do is this:
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What's the scope of a variable initialized in an if statement?
...ked only at runtime -- that is, when you get to the print x statement. If __name__ didn't equal "__main__" then you would get an exception: NameError: name 'x' is not defined.
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Logical operators (“and”, “or”) in DOS batch
...an implicit conjunction.
IF Exist File1.Dat IF Exist File2.Dat GOTO FILE12_EXIST_LABEL
If File1.Dat and File1.Dat exist then jump the label FILE12_EXIST_LABEL.
See also: IF /?
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Read a zipped file as a pandas DataFrame
... you want to read a zipped or a tar.gz file into pandas dataframe, the read_csv methods includes this particular implementation.
df = pd.read_csv('filename.zip')
Or the long form:
df = pd.read_csv('filename.zip', compression='zip', header=0, sep=',', quotechar='"')
Description of the compr...
Extract subset of key-value pairs from Python dictionary object?
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If you're using Python 3, and you only want keys in the new dict that actually exist in the original one, you can use the fact to view objects implement some set operations:
{k: bigdict[k] for k in bigdict.keys() & {'l', 'm', 'n'}}
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.trim() in JavaScript not working in IE
...han.com/archives/faster-trim-javascript
– Daniel Vassallo
Feb 22 '10 at 0:53
92
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Docker - how can I copy a file from an image to a host?
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Actually, I use docker run --rm --entrypoint tar _image_ cC _img_directory_ . | tar xvC _host_directory_
– caligari
Nov 30 '17 at 11:04
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Should I declare Jackson's ObjectMapper as a static field?
...hey are fully immutable, thread-safe, meaning that it is not even theoretically possible to cause thread-safety issues (which can occur with ObjectMapper if code tries to re-configure instance).
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Any way to write a Windows .bat file to kill processes? [closed]
...out of my IDE. Yes, these are processes from programs that my company installs on my machine for security and compliance. What I'd like to do is have a .bat file or script of some kind with which I can kill the processes in question.
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