data-management

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Collapse data frame by group using different functions on each variable

Define df<-read.table(textConnection(\'egg 1 20 a egg 2 30 a jap 3 50 b jap 1 60 b\')) s.t. > df V1 V2 V3 V4[详细]

2023-03-16 12:16 分类：问答
Editing cell entries in a variable in a data frame inside a list of data frames

Define: > dats <- list( df1 = data.frame(a=sample(1:3), b = as.factor(rep(\"325.049072M\",3))),[详细]

2023-03-14 08:20 分类：问答
How do I make doSMP play nicely with plyr?

This code works: library(plyr) x <- data.frame(V= c(\"X\", \"Y\", \"X\", \"Y\", \"Z\" ), Z = 1:5) ddply(x, .(V), function(df) sum(df$Z),.parallel=FALSE)[详细]

2023-02-22 02:34 分类：问答
How to create, structure, maintain and update data codebooks in R?

In the interest of replication I like to keep a codebook with meta data for each data frame. A data codebook is:[详细]

2023-02-17 12:45 分类：问答
How to manage application data while the application is running? (frequent IO versus more memory usage)

I have a general question about desktop applications. My friend and I were discussing about how application data should be managed while the application is running. We were arguing over two methods an[详细]

2023-02-10 06:06 分类：问答
VB.NET: Properly manage data from XML

Good morning all. I\'m relatively new to the Visual Basic realm (although a traditional web based script developer), i\'ve come to ask you a question.I am reading data from an XML file.This local XML[详细]

2023-01-23 15:08 分类：问答
Where to put data management rules for complex data validation in ASP.NET MVC?

I am currently working on an ASP.NET MVC2 project. This is the first time I am working on a real MVC web application. The ASP.NET MVC website really helped me to get started really fast, but I still h[详细]

2022-12-31 09:50 分类：问答
best way to store data locally and update from web from time to time?

I have created an app which displays information in a organized manner about cultural places. The information is subject to changes, so I want it to be downloaded from the web. But not everytime. Only[详细]

2022-12-19 05:11 分类：问答
Handle rollbacks for data edits in a multi-user environment?

How to you typically handle roll backs for data edits in a multi-user environment? Do you identify the transaction and build a graph of any subsequent dependent transactions and then roll them all bac[详细]

2022-12-13 00:27 分类：问答