R loop variable names
R loop variable names. If the loop can be replaced by a vector operation (or apply), it probably should be. name(variable)) print(as. table is sorted automatically. frame objects. Suppose you have a list of all sorts of information on New York City: its population size, the names of the boroughs, and whether it is the capital of the United States. csv. Notice that you need double square brackets - [[ ]] - to select the list elements in loop version 2. Actually I think this one s quite straightforward: I am trying to write a loop that will show me all unique values for each of the variables of a given data frame (let s call it "data"). c()) but is the assignment operator (named parameters use =). list <- list (csv1, csv2) names (object. A variable can have a short name (like x and y) or a more descriptive name (age, carname, total_volume). [R] loops: pasting indexes in variables names Dimitris Rizopoulos dimitris. VARIABLE to indicate it. Nov 18, 2015 · Loop through files in a directory and create variables with file names. Hot Network Questions Basically, what we are doing is that we 'improve' your instruction variable_name="10" so that it becomes variable_name="10" %>% as. These different columns all have the same variable name but a counter at the end. Jan 30, 2020 · This is my first time creating an R package. Share. Oct 10, 2013 · If you want to sort on the rank, you can do that with DT[order(State,r)]. example: `123_mtcars` <- mtcars View(`123_mtcars`) If you would prefer to create a naming convention or just to remove numbers from each dataframe name you could do that in your loop and use the new variable in your assign statement. e. csv,, data100. All processors assign the same string to the variable. See ?assign. May 29, 2015 · I am trying to write a function that will take a data. It takes as a first argument "a variable name, given as a character string. So, now I want to understand why the solution that I thought was the simplest Suppose I have 4 variables in R that belong to dataset data1 and are named x1, x2, y1, y2, and I want to use a loop to create the following variables zi = xi*yi for i=1,2 that will also belong to data1. frame <- # create your data frame here. May 26, 2019 · Passing strings as variables names in R for loop, but keeping names in results. 6k63382. This may be helpful in answering your question as the assignment of a value can take place anytime later. Any ideas? Dec 29, 2021 · I'm trying to automate the generation of several segmented bar plots. This is perfectly legal and works because data. csv, and then you can apply the loop. Loop through variable names in R. Say i have some files like that: data1. Ask Question Asked 6 years, 10 months ago. There are two common ways to do this: Method 1: Use a For Loop. list) <- c ( substitute (csv1), substitute (csv2)) for (i in 1:length (object. frame. The task is to create a list from a set of variables, using the variable names as names for each element in the list, e. csv). – It creates a env-variable, df, that contains two data-variables, x and y. Jun 29, 2015 · get() doesn't return the named object in a way that can be modified without first assigning it to another variable (which would mean the original variable is left unaltered). So here are your options -. Describe what an equation or model represents with variable names. Feb 26, 2024 · Adding Suffix with Variable Name; Change Character Case; Replace Character ; Changing Variable Names With Python Using Prefix . Variable Names. The first variables in my data frame are anagraphical (id, names, etc) so the loop should run for all columns except the first 9. I'm trying the following code, but all it does is generate a plot called px and then stop running: aes(x = mc_qx, fill = test_category)) +. Jul 25, 2017 · assign dynamic variable names using a loop and mutate from dplyr. The loop prints each element as a 1-tuple (on its own line). e. The problem arises when I want to add the string element of the loop (e. Sep 29, 2017 · Ok, I'll post an answer. ) every time through the loop and in the end you would only have the last one, all others would have been rewriten by the newer ones. Not that this is to be preferred. girlheight respectively. " and as the second argument the object you want to assign to that variable name. symbol(var. ) and underscore (_). Put aggregations at the end of variable names. rda files takes an unquoted name only and not a variable. You might want to consider these few improvements: Apr 2, 2015 · For the code, <-does not name parameters in a function call (e. Jun 24, 2020 · How to name a variable in a for-loop dynamically in the R programming language. test, an object of class list. Dec 4, 2020 · I want to change the variable (which represents a dataframe column), that is a part of the formula, for looping this formula. I am trying to create multiple linear regression models from a list of variable combinations (I also have them separately as a data-frame if that is more useful!) The list of variables looks like this: Vars x1+x2+x3 x1+x2+x4 x1+x2+x5 x1+x2+x6 x1+x2+x7 The loop I'm using looks like this: Jun 1, 2018 · Here is a solution using := to dynamically assign variable names and helper functions quo name. I do not believe there is a direct way of doing it. 04. They can then be combined into one object right in R. Dec 31, 2013 · I am trying to do: For each unique project name is want create separate variable name containing the desired values. Something like the following: sqlQuery(channel,paste("Select myCol from myTable where myVal =", x, sep="")) Mar 15, 2017 · I want to create a for loop by variable names. I am trying the below code: x=data. A single string is generated using paste that contains the code for the model, and then we use eval and parse to evaluate this string as code. Apr 4, 2018 · You can use base R names() instead. Looping to name variables. be Wed Sep 22 14:27:19 CEST 2004. How to create variables with different names in for Jul 31, 2020 · How to Create Dynamic Variable Names in a For Loop in R. com/name-variables-in-for-loop-dynamica Mar 12, 2018 · for loop in r with variable names. From an answer standpoint, calling rbind in the loop is essentially the same as Simon's answer. I want to read all csv files in and create dataframes of the form fxpair. list) { print Below, I add another line inside the for loop that replaces gss[[i]] in each dataframe in gss_list to the original column names. 40. 312. 2 How to create a variable giving the name as an argument Aug 2, 2017 · Output objects from within a for loop in R, with name changes in each step. frame() attach(agg) r<-as. val and down. For example, R takes the first variable as "variable_1" in the loop, which produces Aug 24, 2019 · R: Loop of variable names in the data frame. This means reshaping your data table from wide (one column per crop type x yield) to long (one column for crop type, one for yield). csv), envir = . ) already had values but I wanted to use a loop and assign the symbols to another variable. frame and create some new variables with names derived from the corresponding variable names in the list and values from the variables named in the list. character(unique(Project)) for(i in length(agg)) { x<-subset(agg,Project==r[i],select=c("Project","Metrics","Value")) assign() #This is where i am making mistake while Aug 14, 2013 · I have a vector of different column names and I want to be able to loop over each of them to extract that column from a data. A very simple example would be if I have two variables, say boy heights and girl heights, and wanted to store the average boy and girl heights in the variables avg. I hope that makes it more clear. "USA") to my created name "predictions_[i]" or "test_RF_[i]", so that I can get a variable that is called: "predictions_USA" or "test_RF_USA" as well as "predictions_VEN Mar 9, 2018 · Pusheenicorn. So, if I have a file named "2503" in my directory, I want to create a dataframe in R called "t2503". Improve this answer. R - variable name in loop. The code below can better describe what I mean. data[weight != weight_n,c("serial ","weight","weight_n") , drop = F] for each and every variable. However the usethis::use_data() function which creates the . Improper construction of formula objects. for (i in colnames(df)){. How can I turn a part of the filename into a variable when reading multiple text files? 1. I edited your first example to make it more clear of how my data is structured. 4) Example 3: Store for-Loop Results in Vector by Appending. Only after all calculations are done, the Apr 26, 2021 · If you only pass one variable at a time, using the ellipsis looks quite overkill and makes things complicated. csv, data2. temp=list() # need empty list with a name. Adopt conventions for naming and formatting across Apr 17, 2018 · Initially, the string “1” is assigned to the variable. How can I loop over all the variables? I was trying. In this case it will be a list of data. Jul 9, 2019 · R - variable name in loop. for (i in colnames(df[4:7])) {. ) Mar 2, 2015 · You can use get() to return a variable reference based on a string of its name: > x <- 1:10 > get("x") [1] 1 2 3 4 5 6 7 8 9 10 So, yes, you could iterate through Mar 5, 2020 · Alternatively, you may want to use lapply () with setNames () for each file, then use list2env () to set to your environment. Jun 23, 2012 · @Justin, print(seq(1,72,2)) does produce different output. Previous message: [R] loops: pasting indexes in variables names Next message: [R] loops: pasting indexes in variables names Messages sorted by: Sep 22, 2020 · 2. But when I store the different variables in a vector with quotation marks, the variables cannot be used for the t-test as they are saved with the quotation marks. In the examples in this book, the arguments to the for() function are generally going to follow this pattern: 1️⃣An index variable, which is also sometimes called a “counter,” to the left of the keyword in. the [ , ] syntax works because data. In some programming languages you one can do something like this data +{ x }+ . Then it extracts the data-variable x out of the env-variable df using $. I want to create a loop that stores the output of t-tests for several variables in a data frame. Feb 28, 2022 · Since you're already into the tidyverse {dplyr}, you could also leverage one of the "tidy" principles: one column per variable. mm I am having trouble creating the dataframe names in the loop for assignment from the read. Using R dplyr::mutate() with a for loop and dynamic variables. Each time, I calculte the max between each two variables, and define a new one in data df. rizopoulos at med. name)) # outputs 5 Or more simply: get(var. table tutorial or the FAQ. Adding new columns and column names in a loop in R. Creating new variables using other variable names May 28, 2015 · In R, we usually don't use loops for such operations. Hot Network Questions Super capacitors derating R is not meant to have a ton of global variables - instead of Season1 Seaons2 etc you should definitely have a list of seasons. Naming variables and assigning values inside the loop in R. list2env (lapply (setNames (files, names), read. A separate environment for the data objects is a good idea. 2) Example 1: Loop Through Vector in R (Basics) 3) Example 2: Looping Over Character Vectors. GlobalEnv) If you find it more readable, you can also write this with piping. Need as. How you do that depends on what you mean by "merge" though. You are making one newbie mistake and one more sophisticated mistake: Newb mistake: failing to index successive items upon assignment, i. – joran. Dec 22, 2020 · imagine I want to go through a loop and when I find the value that I am interested in, I want to use that value as a new variable name. Follow for loop in r with variable names. Jan 11, 2018 · R generate file names in loop. Name variables with names given in a list using a loop. How to name a column using cbind, in a loop. Apr 1, 2011 · In my case the symbols I create (Tax1, Tax2, etc. You can then loop through the list and use the replacement syntax to change the columns. name[i], d. create a new variable in each iteration. But this code doesn't work. Not so newb mistake. New variables look like this:var1_1, var1_2 Jan 30, 2012 · The basic answer to the question in the title is eval(as. But this code that I have written does not do the job. First, I create a store, lm. If you use dplyr::select you can select columns by name and position in the same command. There are thirteen variables that I'm trying to loop over, named as per the following convention: mc_q#. extracting variable from file names in R. In your code you are assigning the output of lm(. Lookup in an environment is faster than in vector or list. (I'm only iterating 1:1 below since the problem occurs isn't related Jun 9, 2018 · It can be a good idea to use assign when there are many variables and they are looked up frequently. var. variable = paste0("a", i) mean = mean(as. I think creating the variables dynamically within the loop is best in order to automate the naming of the variables and how many are created. The intention is to create the variable's name based on the value of iterating variable i, then fill the new variable with NA values. VARIABLE" is actually a text string name. Instead rlang::sym(n) I tried get(n), !!as. csv (e. numeric("10") with magrittr pipe-stream syntax. When I try to select a variable from mtcars using a dynamic subset of cols, nether of these work Jul 14, 2016 · For loop variable as column name. g. R generate file names in loop. Sep 22, 2011 · 2. The loop style can also be specified with two arguments N1 and N2. In this case the loop runs from N1 to N2 inclusive, and 1. frame(a1,a2) for (i in 1:2) {. It's important that I want to insert one var at the moment, because I want to work with this variable later, and only then to change it to another one (so, I guess "lapply" with a list of variables wouldn't be a solution?) So inside each loop, I will define a set of linear an nonlinear equations, in which the number of equations and the name of variables depend on the range of the loop. loop over variable names in R and do a tabulation of the variable within the loop. kuleuven. Mar 14, 2012 · The loop below, then, should create variables somename0, with values 0,0,0,0, somename1, with values 1:4, and somename2 with values 2,4,6,8. ), it cannot be followed by a digit. I will use the dataset mtcarsas an example. , overwriting earlier values with new values. These variables are defined as follows: Feb 8, 2022 · df = data. 6) Example 5: Break for-Loop Based on Logical Condition. numeric, which is an equivalent of variable_name=as. tucson function to each dataframe. : a <- 2 b <- 'foo' c <- 1:4 I have been wondering if anybody knows a way to create a loop that loads files/databases in R. Hence, the following should work: Basically, what we are doing is that we 'improve' your instruction variable_name="10" so that it becomes variable_name="10" %>% as. Rules for R variables are: A variable name must start with a letter and can be a combination of letters, digits, period (. Jun 10, 2021 · 1. val) and different file names. This makes a lot of manipulations easier. If it starts with period (. The correct way of doing this in R is storing your data frames in a named list. It uses a for loop to iterate through the original names, creates new names with the prefix, and Jan 31, 2020 · 1. It only knows the values. 3. We've already defined a list nyc containing this information (source All for loops start with the for() function. #Select columns by position. VARIABLE + 1 # can't do this because "USER. How to create variables with different names in for Mar 24, 2011 · The csv file names are of the form fxpair-yyyy-mm. geom_bar(position = "fill") +. frames are also lists (just with more structure to them), and lists use the [[ ]] notation to index individual elements (such as vectors in this case). d. Reserved words Jul 24, 2012 · Then, create your for loop and do the following to give the data frames the names you want: for (i in 1:10){. You could simply do: df[paste0("highrev", 1:6)] <- (df[paste0("rev", 1:6)] > 500) + 0 df # store rev1 rev2 rev3 rev4 rev5 rev6 highrev1 highrev2 highrev3 highrev4 highrev5 highrev6 # 1 a 500 260 500 480 500 510 0 0 0 0 0 1 # 2 b 200 100 150 200 68 80 0 0 0 0 0 0 # 3 c 600 450 610 600 750 1000 1 0 1 1 1 1 # 4 d 400 45 350 750 350 400 0 0 0 1 Jul 11, 2016 · Note that I am well aware of several other alternatives to do the same loop renaming over several data frames without using names(), but this was a far simpler, more intuitive alternative (I thought) and I can't see why the loop seems incapable of implementing it. data['nam' != 'nam'_n,c("serial ",'nam','nam'_n) , drop = F] } Jul 5, 2012 · The code below gives an example of how to loop through a list of variable names as strings and use the variable name in a model. Assigning multiple column names at once Mar 21, 2021 · Notice also - akrun above suggests using [[ ]] to refer to named elements of a data. 1. 1 "For" loop with column names as index. Dec 18, 2012 · Within the loop, I want to create files by concatenating a "t" with each individual files name. Construct variable name using a for-loop. for (nam in colnames(df)) {. Jan 9, 2016 · Thanks Mike. Oct 8, 2020 · Often you may want to loop through the column names of a data frame in R and perform some operation on each column. symbol(variable_name_as_string)) as Josh O'Brien uses. Reading files in For-loop fashion in R. I am trying to include 39 different datasets into the pre-loaded data for my package. variable names in for loop. Renaming a variable through a loop. Creating a loop over variables' names. Oct 5, 2020 · The simplest solution is to reference the original names using backticks. R: Using the "names" function on a dataset created within a loop. Each time a next command is used with the variable name, the next string (“2”, “3”, etc) is assigned. frame) } Now you will end up with ten data frames with ten different names. Both, variable and file names I have store on a character vector that I've created. The goal of this tutorial is to learn how to name variables inside loops or using arguments. For loop variable as column name. Viewed 760 times . frame are also 2-dimensional objects with rows and columns. Iterating through variable names in R. Moreover, your example did not seem to work with several variables (group_and_summarize_demo(mtcars, cyl, vs)). csv statements Feb 21, 2019 · R - variable name in loop. Perform for-loop inside data 1) Theoretical Workflow of for-Loops. I'm using dplyr version 1. example: Apr 16, 2015 · How to Create Dynamic Variable Names in a For Loop in R. VARIABLE <- USER. name) # 5 Nov 29, 2017 · R loop change variable names. 2. On top of that I wish to create numerous mean variables using the number in the loop (for instance mean1 and mean2 in the Jun 30, 2018 · R - variable name in loop. I believe it will work with your dataset. name(n) as stated Use dynamic variable names in dplyr . ex: no_its <- 3. yyyy. What I failed to point out is that i want to make changes over a set of different variables (different columns in my data frame). Then we evaluate this expression within current environment. In base R, you can either select the columns by position or by name, you can't combine them both in one command. Moreover, being the data is wide, I have repeated variables (that should have the same prefix) in the columns representing different years (10 Jun 8, 2020 · Note that variable "rf150" is created inside the loop without any problem (don't show the code here). Jun 30, 2017 · Note: I changed your variable names, try to avoid using function names as a variable name. Thank's! Jun 30, 2017 · Note: I changed your variable names, try to avoid using function names as a variable name. csv the system recognizes it like datax. And i have these vectors that are generated using for loop that are in variable vec. DEFINED. The effect of this is that your resultant data object is a list. name(mean)) } This actually doesn't work, since it is not taking the variable values but the variable as a name. So OP committed 2 cardinal sins of R - trying to use one sin to solve the other - which is why the misuse will be so glaring to a seasoned R user Nov 27, 2019 · As the GLM model works when I substitute varlist[i] with the respective variable names age and doc, I would guess the issue stems from how the characters are read by R when substituting the variable name? (I have 26 variables but posting two only for convenience. I think this blurring of the meaning of “variable” is a really nice feature for interactive data analysis because it allows you to refer to data-vars as is, without any prefix. table package also allows for a key -- a vector of columns on which the data. So for a 2 objects system and a specific time increment I might have (in Python): Feb 1, 2015 · I have a function that uses a list of data frames (variables) and gives as output two data frames (for every data frame in the list) which I want to save each one with a different variable name (instead of up. Rather than assigning the read-in data to the dataframe, I'm just Jul 21, 2011 · Please help me with naive question (already googled, and tried a lot of variations, but failed): How save files with the variable in the file name for write. ac. formula. some operation. table in R? Script loop over the files in dir, apply some functions and then save results into the file with the same name but additional ending. The data. Jun 29, 2017 · you can "Assign a value to a name in an environment" using assign. There are other benefits to setting a key as well that you can read about in a data. Modified 6 years, 10 months ago. AUDJPY-2009-05. 0. So the above two answers gave me a way to accomplish this. gss_list % summarize(n = n()) %>% ungroup() colnames(gss_list[[i]])[1] Because I often work with categorical data, I find myself making lots of quick, sorted counts of variables in a dataset. How can I get mutate(), ifelse and lm to use dynamic name as variable name? Aug 28, 2018 · R loop change variable names. Next, I want to read the data in using the r. Here is a simplified version. Use descriptive loop indexes instead of i, j, k. Therefore data = dynamic_name_from_for_loop May 10, 2018 · R - variable name in loop. I'm sure this is something easy Mar 21, 2021 · I am trying to create a loop in R which for each iteration stores the calculations in the loop in a variable with a unique name. name, 5) eval(as. "I believe the solution is to dynamically name the data frame": No! Please don't! Initialize an empty list of length 100 and place each data set in the list in turn. This is how you tell R that you are about to write a for loop. – Jun 5, 2020 · Waldi. Here I want the name Bob to be a new variable containing the character value "my_name". boyheight and avg. Feb 22, 2018 · But before doing this, I want to rename all the variable column names. Creating new variables using other variable names with a loop in R. Mar 17, 2013 · USER. Mar 2, 2015 · You can use get() to return a variable reference based on a string of its name: > x <- 1:10 > get("x") [1] 1 2 3 4 5 6 7 8 9 10 So, yes, you could iterate through Nov 16, 2021 · Use descriptive variable names; Use function parameters or named constants instead of magic numbers. R loop change variable names. I have a data, and vectors conatin name of variables, from these vectorsi calculate the sum of variables contained in the vector and i want to put the result in a new variables that have diffrent names. Maybe this workaround works for you: object. cols <- colnames(d) for (i in cols[-1]) {. I am therefore trying to apply the unqiue() fct. Dynamically change part of variable name in R. This eliminates the need for the for () loop and your i counter. For example, consider the data set mtcars and some variable names stored in a character vector cols. The opposite (get an object based on its name is get). This could be useful if we don’t know how many variables we want to create. More details: https://statisticsglobe. May 2, 2016 · I want to compare. assign(df. } Method 2: Use sapply () sapply(df, some operation) This tutorial shows an example of how to use each of these methods in Jul 19, 2021 · The main idea is replace n by v1 and v5. The R idiom would be to use an apply type function instead of a loop. counter <- 0. R does not remember that i has been created using csv1 and csv2. I want instead to refer to jimsfilename, but all I have is USER. frame, a list (or a character vector) of variable names of the data. In this example, below Python code below adds the prefix “ var_ ” to each variable name in the list original_names. let say i have three vectors. May 20, 2016 · so I already found some related topics but somehow failed to apply them to my case. For your second question about the coefficients: Nov 4, 2012 · In R, I'm writing a for-loop that will iteratively create variable names and then assign values to each variable. name = "x" assign(var. com/name-variables-in-for-loop-dynamica May 2, 2016 · R: Loop of variable names in the data frame. Use item_count instead of num. 5) Example 4: Nested for-Loop in R. Nov 18, 2014 · Adding variable name to column in for statement. rk st dy al of sq bm hg vc np