pandas dataframe, copy by value

pandas dataframe, copy by value

I noticed a bug in my program and the reason it is happening is because it seems that pandas is copying by reference a pandas dataframe instead of by value. I know immutable objects will always be passed by reference but pandas dataframe is

EF: Include with where clause

EF: Include with where clause

As the title suggest I am looking for a way to do a where clause in combination with an include.Here is my situations:I am responsible for the support of a large application full of code smells.Changing too much code causes bugs everywhere

StreamCorruptedException: invalid type code: AC

StreamCorruptedException: invalid type code: AC

My problem is when it tries to read the object the second time, it throws the exception: java.io.StreamCorruptedException: invalid type code: AC at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1356) at java.io.ObjectIn

String literals: Where do they go?

String literals: Where do they go?

I am interested in where string literals get allocated/stored.I did find one intriguing answer here, saying: Defining a string inline actually embeds the data in the program itself and cannot be changed (some compilers allow this by a smar

Aren't promises just callbacks?

Aren't promises just callbacks?

I've been developing JavaScript for a few years and I don't understand the fuss about promises at all.It seems like all I do is change:api(function(result){ api2(function(result2){ api3(function(result3){ // do work

How do I use reflection to call a generic method?

How do I use reflection to call a generic method?

What's the best way to call a generic method when the type parameter isn't known at compile time, but instead is obtained dynamically at runtime?Consider the following sample code - inside the Example() method, what's the most concise way t

Syntax error due to using a reserved word as a table or column name in MySQL

Syntax error due to using a reserved word as a table or column name in MySQL

I'm trying to execute a simple MySQL query as below:INSERT INTO user_details (username, location, key)VALUES ('Tim', 'Florida', 42)But I'm getting the following error: You have an error in your SQL syntax; check the manual that corresponds

What is the explicit promise construction antipattern and how do I avoid it?

What is the explicit promise construction antipattern and how do I avoid it?

I was writing code that does something that looks like:Using the Promise constructor:function getStuffDone(param) { return new Promise(function(resolve, reject) { myPromiseFn(param+1) .then(function(val) { resolve(val);

What is `type_info::before` useful for?

What is `type_info::before` useful for?

According to cplusplus.com, the std::type_info::before() function... Returns true if the type precedes the type of rhs in the collation order. The collation order is just an internal order kept by a particular implementation and is not ne

C++: Create abstract class with abstract method and override the method in a subclass

C++: Create abstract class with abstract method and override the method in a subclass

How to create in C++ an abstract class with some abstract methods that I want to override in a subclass? How should the .h file look? Is there a .cpp, if so how should it look?In Java it would look like this:abstract class GameObject{ pu

How to save data with Python?

How to save data with Python?

I am working on a program in Python and want users to be able to save data they are working on. I have looked into cPickle; it seems like it would be a fast and easy way to save data, it seems insecure. Since entire functions, classes, et

make: implicit rule to link c++ project

make: implicit rule to link c++ project

I am working my way through a make tutorial. Very simple test projects I am trying to build has only 3 files: ./src/main.cpp ./src/implementation.cpp and ./include/header.hpp This is the make file.VPATH = src includeCPPFLAGS = -I includemai

How to fetch the tables list in database in Laravel 5.1

How to fetch the tables list in database in Laravel 5.1

I need to list out the tables in database, I found the query for SHOW TABLES LIKE 'merTrans%'get the tables but how could I use the foreach to get the table names in Laravel 5.1? 1:To list out the tables in database you can do$tables =

How do I select a .Net application configuration file from a command line parameter?

How do I select a .Net application configuration file from a command line parameter?

I would like to override the use of the standard app.config by passing a command line parameter. How do I change the default application configuration file so that when I access ConfigurationManager.AppSettings I am accessing the config fi

How to deserialize class without calling a constructor?

How to deserialize class without calling a constructor?

I'm using Json.NET in my WCF data service.Here's my class (simplified):[DataContract]public class Component{ public Component() { // I'm doing some magic here. }}How can I deserialize that class without invoking a constructo

making gcc prefer static libs to shared objects when linking?

making gcc prefer static libs to shared objects when linking?

When linking against libraries using the -l option (say -lfoo), gcc will prefer a shared object to a static library if both are found (will prefer libfoo.so to libfoo.a). Is there a way to make gcc prefer the static library, if both are fou

When would JavaScript == make more sense than ===?

When would JavaScript == make more sense than ===?

As Which equals operator (== vs ===) should be used in JavaScript comparisons? indicates they are basically identical except '===' also ensures type equality and hence '==' might perform type conversion. In Douglas Crockford's JavaScript: T

djangorestframework: Filtering in a related field

djangorestframework: Filtering in a related field

Basically, I want to filter out inactive users from a related field of a ModelSerializer. I tried Dynamically limiting queryset of related field as well as the following:class MySerializer(serializers.ModelSerializer): users = serializers.

Mongoose create multiple documents

Mongoose create multiple documents

I know in the latest version of Mongoose you can pass multiple documents to the create method, or even better in my case an array of documents.var array = [{ type: 'jelly bean' }, { type: 'snickers' }];Candy.create(array, function (err, jel

Django ORM, group by day

Django ORM, group by day

I am trying to group products by DAY, however date_created is a datetime field.Product.objects.values('date_created') \ .annotate(available=Count('available_quantity'))returns:[ {'date_created': datetime.datetime(2012, 4, 1

multiprocessing with large data

multiprocessing with large data

I am using multiprocessing.Pool() to parallelize some heavy computations.The target function returns a lot of data (a huge list). I'm running out of RAM.Without multiprocessing, I'd just change the target function into a generator, by yield

Same named function with multiple arguments in PHP

Same named function with multiple arguments in PHP

I started off OOP with Java, and now I'm getting pretty heavy into PHP. Is it possible to create multiples of a function with different arguments like in Java? Or will the interpreted / untyped nature of the language prevent this and cause

Django error - matching query does not exist

Django error - matching query does not exist

I finally released my project to the production level and suddenly I have some issues I never had to deal with in the development phase.When the users posts some actions, I sometimes get the following error.Traceback (most recent call last)

Why is null not allowed for DateTime in C#?

Why is null not allowed for DateTime in C#?

Why it is not allowed to assign null to a DateTime in C#? How has this been implemented? And can this feature be used to make your own classes non-nullable?Example:string stringTest = null; // OkayDateTime dateTimeTest = null; // Compile er

Split/explode comma delimited string with Sybase SQL Anywhere [duplicate]

Split/explode comma delimited string with Sybase SQL Anywhere [duplicate]

This question already has an answer here: How do I split a string so I can access item x? 40 answers UPDATE: Someone marked this question as du