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What are the -Xms and -Xmx parameters when starting JVM?
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The flag Xmx specifies the maximum memory allocation pool for a Java virtual machine (JVM), while Xms specifies the initial memory allocation pool.
This means that your JVM will be started with Xms amount of memory and will be able to use a maximum of Xmx amount of ...
How do I use NSTimer?
...ewController
double timerInterval = 1.0f;
- (NSTimer *) timer {
if (!_timer) {
_timer = [NSTimer timerWithTimeInterval:timerInterval target:self selector:@selector(onTick:) userInfo:nil repeats:YES];
}
return _timer;
}
- (void)viewDidLoad
{
[super viewDidLoad];
[[NSRu...
CSS transition shorthand with multiple properties?
...n: height 0.3s ease-out, opacity 0.3s ease 0.5s;
Or just transition them all:
-webkit-transition: all 0.3s ease-out;
-moz-transition: all 0.3s ease-out;
-o-transition: all 0.3s ease-out;
transition: all 0.3s ease-out;
Here is a straightforward example. Here is another one with the delay propert...
Pandas aggregate count distinct
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How about either of:
>>> df
date duration user_id
0 2013-04-01 30 0001
1 2013-04-01 15 0001
2 2013-04-01 20 0002
3 2013-04-02 15 0002
4 2013-04-02 30 0002
>>> df.groupby("date").agg({"duration": np.sum, "use...
How to fix Python indentation
...py script that you find in the Tools/scripts/ directory of your Python installation:
Change Python (.py) files to use
4-space indents and no hard tab
characters. Also trim excess spaces
and tabs from ends of lines, and
remove empty lines at the end of
files. Also ensure the last line ...
SignalR - Sending a message to a specific user using (IUserIdProvider) *NEW 2.0.0*
...ar chat = $.connection.chatHub;
// Create a function that the hub can call to broadcast messages.
chat.client.addChatMessage = function (who, message) {
// Html encode display name and message.
var encodedName = $('<div />').text(who).html();
var encodedMsg = $(...
Merge (with squash) all changes from another branch as a single commit
In Git, is there a way to merge all changes from one branch into another, but squash to a single commit at the same time?
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How can I validate a string to only allow alphanumeric characters in it?
How can I validate a string using Regular Expressions to only allow alphanumeric characters in it?
10 Answers
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How to get a list of column names on Sqlite3 database?
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PRAGMA table_info(table_name);
will get you a list of all the column names.
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Find duplicate lines in a file and count how many time each line was duplicated?
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This is what I do however algorithmically this is doesnt seem to be the most efficient approach (O(n log n)*avg_line_len where n is number of lines). I'm working on files that are several gigabytes large, so performance is a key issue. I wonder whether there is ...