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mongodb: insert if not exists
...u want to do an "upsert". MongoDB has built-in support for this. Pass an extra parameter to your update() call: {upsert:true}. For example:
key = {'key':'value'}
data = {'key2':'value2', 'key3':'value3'};
coll.update(key, data, upsert=True); #In python upsert must be passed as a keyword argumen...
How do I use the nohup command without getting nohup.out?
...ting for you to bring it back to the foreground and type something. So the extra-safe version looks like this:
nohup command </dev/null >/dev/null 2>&1 & # completely detached from terminal
Note, however, that this does not prevent the command from accessing the terminal directl...
How to reverse a 'rails generate'
...y using the rails generate command.
For example:
rails g model Home name:string
creates a model named home with attribute name. To remove the files and code generated from that command we can use
rails d model Home
sh...
Maven: How to include jars, which are not available in reps into a J2EE project?
... install:install-file -Dfile=cassandra-jdbc-1.1.1.jar -DgroupId=org.apache-extras.cassandra-jdbc -DartifactId=cassandra-jdbc -Dversion=1.1.1 -Dpackaging=jar"
– Mazrick
Jun 30 '12 at 3:14
...
Java8 Lambdas vs Anonymous classes
...s neat as compared to Anonymous Inner Class (AIC)
public static void main(String[] args) {
Runnable r = new Runnable() {
@Override
public void run() {
System.out.println("in run");
}
};
Thread t = new Thread(r);
t.start();
}
//syntax of lambda ...
Error message 'Unable to load one or more of the requested types. Retrieve the LoaderExceptions prop
...causes the error goes here.
}
catch (ReflectionTypeLoadException ex)
{
StringBuilder sb = new StringBuilder();
foreach (Exception exSub in ex.LoaderExceptions)
{
sb.AppendLine(exSub.Message);
FileNotFoundException exFileNotFound = exSub as FileNotFoundException;
i...
Find the nth occurrence of substring in a string
...tive approach would be the usual way, I think.
Here's an alternative with string-splitting, which can often be useful for finding-related processes:
def findnth(haystack, needle, n):
parts= haystack.split(needle, n+1)
if len(parts)<=n+1:
return -1
return len(haystack)-len(pa...
How to use ScrollView in Android?
...on one of the views in the LinearLayout makes that view expand to fill any extra space.
Here is the XML
<?xml version="1.0" encoding="utf-8"?>
<ScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match...
App Inventor 2 项目合并工具 AIMerge · App Inventor 2 中文网
...ick block
The SetTime.Click block opens the SetTime screen. Note that the string assigned to screenName must be exactly what was decided in advance as the name of the second screen.
Figure 3: CountDownScreen1’s Screen1 OtherScreenClosed block
The Screen1.OtherScreenClosed receives the number ...
how to emulate “insert ignore” and “on duplicate key update” (sql merge) with postgresql?
...n.
You can of course wrap this in a function if you don't want to put the extra code on the client side. You also need a loop for the very rare race condition in that thinking.
There's an example of this in the documentation: http://www.postgresql.org/docs/9.3/static/plpgsql-control-structures.ht...