Category: Replace in dataframe r

A common way to treat missing values in R is to replace NA with 0. One common issue for replacing NA with 0 in an R database is the class of the variables in your data. However, if you have factor variables with missing values in your dataset, you have to do an additional step. As you have seen in the previous examples, R replaces NA with 0 in multiple columns with only one line of code. However, we need to replace only a vector or a single column of our database.

As you can see, there are many different ways in R to replace NA with 0 — All of them with their own pros and cons. If you want to investigate even more possibilities for a zero replacement, I can recommend the following thread on stackoverflow.

Beside the question how to find and replace NA with 0 in R, the question arises whether such a replacement screws our statistical data analyses. As most of the time in statistics, the answer is: It depends! If it is meaningful to substitute NA with 0, then go ahead. Then it would be logical to change NA to 0, since these people basically spend zero money for holidays. However, if we have NA values due to item nonresponse, we should never replace these missing values by a fixed number, i.

As you can see in the example, the density of a normal distribution would be highly screwed toward zero, if we just substitute all missing values with zero as indicated by the red density. The statistical analysis with missing data is a whole domain of statistical research. The imputation of missing values is one of the most popular approaches nowadays. When data is imputed, new values are estimated on the basis of imputation models in order to replace missing values by these estimates. Another popular approach is casewise deletion also called listwise deletion.

In casewise or listwise deletion, all observations with missing values are deleted — an easy task in R. This approach has its own disadvantages, but it is easy to conduct and the default method in many programming languages such as R. To change NA to 0 in R can be a good approach in order to get rid of missing values in your data.

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Or are you using other ways? Let me know in the comments! Moritz, S. Package imputeTS. Wickham, H. Package dplyr. The header graphic of this page shows a correlation plot of two continuous i.

The dark blue dots indicate observed values. I simply desired to say thanks once more. It seemed to be the alarming dilemma in my opinion, but discovering the very professional fashion you solved it took me to cry for fulfillment.

Most likely you have never come across all of us. This is brilliant! Thank you for taking the time to put together such a well versed set of examples. Your email address will not be published. Post Comment. You will find a summary of the most popular approaches in the following.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

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Having a data frame, how do I go about replacing all particular values along all rows and columns. Say for example I want to replace all empty records with NA 's without typing the positions :. Since PikkuKatja and glallen asked for a more general solution and I cannot comment yet, I'll write an answer.

You can combine statements as in:. Learn more. Replace all particular values in a data frame Ask Question. Asked 6 years, 5 months ago. Active 1 year ago. Viewed k times. Ronak Shah k 14 14 gold badges 58 58 silver badges bronze badges. Active Oldest Votes. Found it out: df. Interestingly I am not able to replace with null as value. I am getting : java. IllegalArgumentException: Unsupported value type java. String null.

How would you go about using the all columns solution to replace several strings by NAs in the whole dataset? We can use data. You need to insert it in a loop.

Tony benetatos

Why would you use an external library for this use case? Why a loop if this can be solved with one line? How does your answer add value beyond the answers already present?

I don't intend to be harsh, I think I am missing something, hence the questions.

replace in dataframe r

It's much faster for large datasets. It adds an alternative so that the user can choose the best for him. If you want to replace multiple values in a data frame, looping through all columns might help.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. The dark mode beta is finally here.

Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. Once I complete cleaning process, I store the resulting dataframe in destination. I tried df. It isn't working for me. If present, then need to replace. Here row.

replace in dataframe r

I don't want specify the column name or row number while using replace. Please find the code below. Another solution is use str. Learn more. How to remove carriage return in a dataframe Ask Question. Asked 3 years, 11 months ago. Active 26 days ago. Viewed 18k times. Is there any other solution. Can somebody help?

Series row. Saranya Krishnamurthy. Saranya Krishnamurthy Saranya Krishnamurthy 1 1 gold badge 5 5 silver badges 15 15 bronze badges.Values of the DataFrame are replaced with other values dynamically. This differs from updating with. Dicts can be used to specify different replacement values for different existing values. To use a dict in this way the value parameter should be None. For a DataFrame a dict can specify that different values should be replaced in different columns.

The value parameter should not be None in this case.

replace in dataframe r

You can treat this as a special case of passing two lists except that you are specifying the column to search in. For a DataFrame nested dictionaries, e. The value parameter should be None to use a nested dict in this way. You can nest regular expressions as well. Note that column names the top-level dictionary keys in a nested dictionary cannot be regular expressions. This means that the regex argument must be a string, compiled regular expression, or list, dict, ndarray or Series of such elements.

If value is also None then this must be a nested dictionary or Series. For a DataFrame a dict of values can be used to specify which value to use for each column columns not in the dict will not be filled.

Regular expressions, strings and lists or dicts of such objects are also allowed. If True, in place. Note: this will modify any other views on this object e. Returns the caller if this is True. Regex substitution is performed under the hood with re. The rules for substitution for re. Regular expressions will only substitute on strings, meaning you cannot provide, for example, a regular expression matching floating point numbers and expect the columns in your frame that have a numeric dtype to be matched.

However, if those floating point numbers are strings, then you can do this.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

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In the R data frame coded for below, I would like to replace all of the times that B appears with b. NOTE: I managed to solve the problem with gsub but in the interest of learning R I still would like to know how to get my original approach to work if it is possible. Take a look at Index vectors in R Introduction if you don't read it yet. As the data you show are factors, it complicates things a little bit.

To get back to the original factors a further step is required. That is quite simple and I often forget that there is a replacement function for levels. Edit: As noted by Seth in the comments, this can be done in a one-liner, without loss of clarity:.

replace in dataframe r

The easiest way to do this in one command is to use which command and also need not to change the factors into character by doing this:. You have created a factor variable in nm so you either need to avoid doing so or add an additional level to the factor attributes.

R Replace NA with 0 (10 Examples for Data Frame, Vector & Column)

If you are working with character variables note that stringsAsFactors is false here you can use replace:. Learn more. Asked 8 years, 11 months ago. Active 1 year ago. Viewed k times. Factors are useful, and necessary if one is modelling with most of R's modelling code. The correct way of dealing with this is to acknowledge that the data are a factor. If you do want the factor, then there are easy ways to do the manipulation Kenny wants to perform.

Simpson Apr 28 '11 at So factors used to be more popular because of performance, however, now that strings are immutable and hashed the value of factors is less obvious, as most of the base R functionality will just convert them albeit with warnings directly.

I think factors result in a significant number of bugs that I find in peoples R code. Active Oldest Votes. Oriol Prat Oriol Prat 1 1 gold badge 8 8 silver badges 16 16 bronze badges. As noticed in comments this solution works for character vectors so fail on your data. Marek Marek Oh, another, important addition: Doing it like this requires first adding the factor level b to the factor nm.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

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I'm trying to replace a certain string in a large data. I just found the following solution but gsub doesn't preserve the original data. How can I achieve this. You will want to lapply through your data. The result will be a listbut as. Learn more. Asked 6 years, 11 months ago. Active 4 years, 10 months ago. Viewed 23k times. I mean I want to replace a string and don't want to change the layout of the df.

R tutorial - Using Factors in R

Active Oldest Votes. James James RichardSmith That makes the expression return its result visibly to the console. Assignment is normally returned invisibly. Ken Benoit 9, 20 20 silver badges 38 38 bronze badges. Thomas Thomas 38k 9 9 gold badges 89 89 silver badges bronze badges. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. The Overflow How many jobs can be done at home?

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The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I'd like to remove every occurrence of the space. I can extract all the values and make the new strings but I can't put them back in the data frame. Created on by the reprex package v0. Learn more.

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Replace all occurrences of a string in a data frame Ask Question. Asked 5 years ago. Active 11 months ago. Viewed k times. Arun k 17 17 gold badges silver badges bronze badges. Tony Ladson Tony Ladson 2, 1 1 gold badge 19 19 silver badges 26 26 bronze badges. Active Oldest Votes.

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Tim Biegeleisen Tim Biegeleisen k 16 16 gold badges silver badges bronze badges. Use lapply instead - it will save the coercion to a matrix. Or of course the solution in the comment above, from Avinash Raj. Equivalent to "find and replace.

Nettle Nettle 1, 13 13 silver badges 19 19 bronze badges. Brief and legible. NB: coerces factors to characters! Rich Scriven Rich Scriven Ankit Katiyar Ankit Katiyar 1, 12 12 silver badges 26 26 bronze badges. Michelle Michelle 1. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name.

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