Posts by Carlos Cinelli • 16,826 points
232 posts
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2
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answers517
viewsA: Comparing matrices of different sizes in R
You can do this with the merge: resultado <- merge(all_sec, portfolio, all=TRUE) # faz o merge das duas matrizes resultado <- apply(resultado, 2, as.character) # transforma em texto de novo…
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3
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answers389
viewsA: *apply with three-argument functions in R
You can do it directly with apply by separating the three arguments from the line as the parameters. Resultado <- apply(matrix, 1, function(linha) suafuncao(linha[1],linha[2],linha[3])) In this…
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6
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answer3385
viewsA: Replace specified column values in a matrix (R)
In the matrix, when you put the condition ret_matriz==0 you are already making a subset of the whole matrix, rows and columns. So what you have to do in this case is first filter only the columns…
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4
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answers446
viewsA: Function using as arguments successive values of a column (R)
You can use the sapply along with the mapply. Making with a data.frame for example: set.seed(1) dados <- data.frame(x=rnorm(100), y=rnorm(100)) resultados <- sapply(dados, function(col)…
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answers1031
viewsA: Replace Zero and Infinity values in a matrix (R)
You can do it as follows. Below m is your matrix: m[m==0] <- m[row(m)[m== 0], 1] m[is.infinite(m)] <- m[row(m)[is.infinite(m)],1]…
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answers14389
viewsA: How to filter a data frame?
Well, in principle your code is correct, it should subset the data, what may have occurred is some other problem that would only be possible to verify with the specific case. Showing in a sample…
ranswered Carlos Cinelli 16,826 -
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answers14983
viewsA: How to merge multiple dates frames into one
To illustrate, I will create 3 different example data.frames, one with variable x, other with variable y and the other with the variable z for the same individuals id: ### exemplos #### set.seed(1)…
ranswered Carlos Cinelli 16,826 -
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answers15918
viewsA: Delete lines containing NA in a data frame
There are two solutions. If you want to omit all NA from the data.frame, you can use the function na.omit. For example, suppose a date.frame with two columns, where there are NA’s in both columns.…
ranswered Carlos Cinelli 16,826 -
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answer1401
viewsA: Using function to make a subset and plot with only 1 command (R)
There is no R function that will do this automatically, but you can create a function for it. A function that automatically graphs the actions in a certain period would look like this. I’ll use the…
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answer602
viewsA: Minimum value of a row excluding zero (R)
Instead of using the min in the apply, you can apply an anonymous function that selects the minimum only of non-zero numbers (function(x) min(x[x!=0])). For example, in your code it would look like…
ranswered Carlos Cinelli 16,826 -
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answer2705
viewsQ: How to sort array of strings disregarding accents?
If I have an array like the following: exemplo = ["Árvore", "Casa", "Computador", "É", "Poste", "Pássaro", "Índia", "Ar", "Ásia"] The exemplo.sort() considers the accentuation of the words to order,…
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4
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answer1449
viewsA: Changing Missing data <NA> by "something else"
The pattern of read.spss is to transform categorical variables into factors (categories, factors). When a variable is a factor, she only accepts what you define as the levels for her. So when you…
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63
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answers5844
viewsQ: Coffeescript, Typescript and Javascript
Among Javascript studies, I found in some places many people suggesting the use of Coffeescript or Typescript to accelerate the development process. If I understand correctly, both are like a…
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4
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answer248
viewsQ: jQuery Unique, difference in Chrome and Firefox?
I’m having an unexpected behavior with the uniquejQuery. The following command: var x = [1,2,1,2]; var y = $.unique(x); document.write(y); Chrome results in 1,2 (which is correct), but in Firefox…
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31
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answers7191
viewsQ: How to put default (default) arguments in a Javascript function?
In R this would be very simple: funcao <- function(x=10) return(x) If you call funcao() without arguments the result will be 10. How to do the same in Javascript? And how to know if there are…
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answer1802
viewsQ: How do prototypes work in Javascript?
It seems to me that the concept of prototype is fundamental in Javascript and even in several places I have read that is one of its strengths. However, this does not seem such a simple concept to…
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answers1021
viewsA: How to add object properties in Javascript?
I got an even more synthetic shape using the jFunk and Underscore. totais = _.chain(jF("*[Regiao]", vendas).get()).groupBy('Regiao').map(function(g, key) { return { type: key, val:…
javascriptanswered Carlos Cinelli 16,826 -
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answers1021
viewsQ: How to add object properties in Javascript?
Suppose an object as follows: vendas = { obs1:{ Venda1:{Regiao:"Norte", Valor: 200}, Venda2:{Regiao:"Sul", Valor:100} }, obs2:{ Venda1:{Regiao:"Norte", Valor: 50}, Venda2:{Regiao:"Sul", Valor:20} }…
javascriptasked Carlos Cinelli 16,826 -
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answer8713
viewsA: How to know the "size" (amount of properties/attributes) of an object in Javascript?
One solution I found was to use the function Object.keys() together with length: Object.keys(vendas).length //2, isto é Obs1 e Obs2 Object.keys(vendas.obs1).length //2, isto é, Venda1 e Venda2 In…
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answer8713
viewsQ: How to know the "size" (amount of properties/attributes) of an object in Javascript?
Suppose an object as follows: vendas = { obs1:{ Venda1:{Regiao:"Norte", Valor: 200}, Venda2:{Regiao:"Sul", Valor:100} }, obs2:{ Venda1:{Regiao:"Norte", Valor: 50}, Venda2:{Regiao:"Sul", Valor:20} }…
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answers954
viewsQ: How to list variables defined within a Javascript scope?
How do I know/list which variables have already been defined within a scope, whether global or local? For example if I set var x, y, z = 10, the result of a possible command to list the variables…
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answers8317
viewsQ: How to delete a variable in Javascript?
I program in other languages, I’m still starting in Javascript. I was testing the mgibsonbr response code to this question and found a difficulty that may be trivial. If I define var x = 0 in the…
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answer5017
viewsQ: Export formatted R to Excel data
Suppose a data.frame like this: tabela <- structure(list(vendedor = structure(1:4, .Label = c("A", "B", "C", "D"), class = "factor"), Total = c(3300, 440, 1020, 200)), .Names = c("vendedor",…
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answer1619
viewsA: The order function in R
The function order does not return the ordered original vector, but returns a vector with the positions so that x stay in ascending order. Thus, to get back the vectorx ordered, you have to put…
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answers19793
viewsQ: Functional Programming and Object-Oriented Programming. What are they and what are their main differences?
What are and what are the main differences between Functional Programming and Object-Oriented Programming?
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answers10198
viewsQ: What are lexical scope and dynamic scope and what are their main differences?
What are lexical scope and dynamic scope and what are their main differences?
asked Carlos Cinelli 16,826 -
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answers412
viewsA: Connecting dots to the 3d regression line
Making with the base charts: First, run the model: model <- loess(Income ~Education + Seniority, data=Income2) Create sequences of x and y: x <-range(Income2$Education) x <- seq(x[1], x[2],…
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answers412
viewsQ: Connecting dots to the 3d regression line
This is the 3d version of this other question. Consider the following data: Income2<-structure(list(X = 1:30, Education = c(21.5862068965517, 18.2758620689655, 12.0689655172414, 17.0344827586207,…
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answers969
viewsA: How to do an optimization with inequality restriction?
In this example, you can define in the function that if the values exceed the constraint, it receives infinite value: fr <- function(x){ if(x[1]+4*x[2] > 3 ){value<-Inf} else{ x1 <- x[1]…
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answers443
viewsA: Reorder categories in a data frame
By creating the factor, you can tell the R what order you want for the levels: df$categorias <- factor(df$categorias, levels=c("Muito baixa","Baixa","Média","Alta","Muito alta") Upshot:…
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answer497
viewsA: How to remove unused categories (levels) in the database
You can use the function droplevels subdf <- droplevels(subset(df, valores <= 3)) Upshot: levels(subdf$categorias) [1] "A" "B" "C" The advantage is that it works for more than one variable…
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answers178
viewsA: Collapsing texts in a single line in a database
You can do with the dplyr using the option collapse of paste: library(dplyr) tabela2<-tabela %>% group_by(ano) %>% summarise(quantidade = n(), nomes = paste(nome,collapse=", ")) Out of…
ranswered Carlos Cinelli 16,826 -
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answers302
viewsA: Connecting the points to the regression line
In the ggplot2 you can use the geom_segment to draw lines between the points and the values predicted by the model. But first you need to run the model "outside" of the gpplot2 to obtain the…
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7
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answers302
viewsQ: Connecting the points to the regression line
Suppose the following database: Income <- structure(list(X = 1:30, Education = c(10, 10.4013377926421, 10.8428093645485, 11.2441471571906, 11.6454849498328, 12.0869565217391, 12.4882943143813,…
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answers693
viewsA: How to know the amount of NA in each variable?
You can use the function colwise of plyr to make its function applicable to data frame columns: Defining the function: library(plyr) quantos.na <- colwise(function(x) sum(is.na(x))) Applying the…
ranswered Carlos Cinelli 16,826 -
3
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answer322
viewsA: Creating a matrix with variables with different correlations in R?
Peter, First of all, you have an extra loop in your code. Note that you are generating an array 1000 by 5. Then you start a loop by k (correlations), then by i (columns), and then by j (lines). See…
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answers830
viewsA: Loop in R with indexing and matrix
You don’t need to use for in this case. Follows a solution with sapply: y <- function(x,z) 5+3*x+4*z set.seed(1) x <- rnorm(1000, mean = 0, sd = 1) z <- c(1, 2, 3, 4, 5)…
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answer168
viewsA: How to vary parameters of an equation?
Suppose you have two parameters a, two parameters b and a value of x: a<- c(1,2) b <-c(3,4) x <- 10 You want to find all the y possible with the four combinations of the parameters, given…
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answers97
viewsA: Subtracting matrices with different arguments
Your object x has dimensions 4x1x1 and the object y only 4x1, you can not subtract objects with different dimensions. If you put the dimensions 4x1 in x works: x<-array(1:4,c(4,1))…
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answers6494
viewsA: How to create inverse matrix in R
Felipe, it is not very clear what the problem is, ideally you would put the code with the (possible) error. But here are some ways to reverse a matrix in the R: Generating an example database: ###…
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answer941
viewsA: How to create invertible random matrices in R
I’m not sure I understand what the problem was, but it’s almost impossible (X'X) do not have inverse in this case, because you will generate 1000 random numbers and only has 2 variables. So I think…
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answer10722
viewsA: How to plot a line chart with different colors depending on the value?
A partial "solution" would be to generate a Spline with many points (about 100 for example) that the colors would be less likely to be in the wrong place. But this solution can spend a lot of memory…
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answer159
viewsA: How to find a table by category with minimum observations?
You can take only the attribute names of which.min: a<-c(rep("agosto",3),rep("janeiro",4),rep("maio",6)) tabela<-table(a) names(which.min(tabela)) [1] "agosto" To better understand, when you…
ranswered Carlos Cinelli 16,826 -
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answers10996
viewsA: Error while converting numbers. How to convert factors to numbers?
In the R, the standard behavior of data.frame is to turn texts into factors. This can generate unexpected results when numbers, during the data import/manipulation process, are misinterpreted as…
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answers10996
viewsQ: Error while converting numbers. How to convert factors to numbers?
In the following example: dados <- data.frame(x=c("11", "10", "20", "15"), y=c("25", "30", "35", "40")) dados x y 1 11 25 2 10 30 3 20 35 4 15 40 When trying to transform the variable x number,…
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answers1491
viewsQ: Strategies to prevent software regression
What programming strategies/best practices can be adopted to minimize the risk of software regression? Questions that can help guide: which "pranks"/bad practices can fool the programmer and leave a…
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answer462
viewsA: How to set up Sublimerepl for Anaconda (Python)?
Inside the folder Packages/User create the folders SublimeREPL/config/Python/ and the file Main.sublime-menu with the following content (format json), where on the line "cmd" you will exchange the…
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answer462
viewsQ: How to set up Sublimerepl for Anaconda (Python)?
I installed Sublimerepl for execute the line or selection directly from Sublime Text 2. Meanwhile, in the same way as in this previous problem, Sublimerepl is not using Anaconda but another version…
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answer4059
viewsQ: How to run the current line in Sublime Text 2? Or, IDE that allows running the current line in Python
In the rstudio (IDE to r) it is possible to run the current line instead of the entire file using ctrl (or cmd) + enter. This is very useful for when you want to test just one piece of code separate…
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15
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answer6546
viewsQ: Naming conventions for variables and functions in Python?
In the R, there is a lot of freedom and variety in function names between packages. Dot names (get.this), names in camel (getThis), names in snake_case (get_this). This has its pros and cons. Why,…