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how do you filter pandas dataframes by multiple columns
...r function using query in pandas. Here you have filtering of df results by all the kwargs parameters. Dont' forgot to add some validators(kwargs filtering) to get filter function for your own df.
def filter(df, **kwargs):
query_list = []
for key in kwargs.keys():
query_list.append(f...
How to change language settings in R
... of the abbreviations can be found here.
Sys.getenv() gives you a list of all the environment variables that are set.
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java get file size efficiently
...97.044
URL sum: 95534, per Iteration: 382.136
File must be caching the calls to the filesystem, while channels and URL have some overhead.
Code:
import java.io.*;
import java.net.*;
import java.util.*;
public enum FileSizeBench {
LENGTH {
@Override
public long getResult() ...
String concatenation: concat() vs “+” operator
...then throwing it away when you create the final String. In practice memory allocation is surprisingly fast.
Update: As Pawel Adamski notes, performance has changed in more recent HotSpot. javac still produces exactly the same code, but the bytecode compiler cheats. Simple testing entirely fails bec...
Spring Data: “delete by” is supported?
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Typically, in an application, you will have @ Service classes/methods and those will be calling the Repositories. And @ Service public methods should be the methods that are marked @ Transactional because transactions are Use Case...
How can I handle R CMD check “no visible binding for global variable” notes when my ggplot2 syntax i
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Just another warning. aes_string does not allow you to use functions to manipulate the x and y values. Say that you would like to log transform y in which case aes_string(x = 'x.values', y='log(y.values)') of course doesn't work. I use these kind of transformations a...
Using PUT method in HTML form
...
XHTML 1.x forms only support GET and POST. GET and POST are the only allowed values for
the "method" attribute.
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What does “The APR based Apache Tomcat Native library was not found” mean?
...ns exactly what it says: "The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path"
The library referred to is bundled into an OS specific dll (tcnative-1.dll) loaded via JNI. It allows tomcat to use OS functionali...
Shell command to sum integers, one per line?
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just used this for a: count all documents’ pages script: ls $@ | xargs -i pdftk {} dump_data | grep NumberOfPages | awk '{s+=$2} END {print s}'
– flying sheep
Jul 10 '13 at 14:42
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How to 'bulk update' with Django?
...ings like incrementing rows:
from django.db.models import F
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
See the documentation.
However, note that:
This won't use ModelClass.save method (so if you have some logic inside it won't be triggered).
No django signals will be emitte...