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Articles by Nizamuddin Siddiqui
Page 81 of 196
How to preserve data frame structure after applying a function in R?
When we apply a function using apply family, by default the output is not in the form of a data frame. If we want to preserve the original data frame structure then we need to set the application of the apply family by setting it to the original data frame with single brackets and no arguments as shown in the below examples.Example1Consider the below data frame −Live Demo> df1 df1Output x1 x2 1 4 2 2 6 2 3 5 2 4 2 1 5 8 4 6 7 2 7 5 3 ...
Read MoreHow to find the unique rows in an R data frame?
A unique row in an R data frame means that all the elements in that row are not repeated with the same combination in the whole data frame. In simple words, we can say that if we have a data frame called df that contains 3 columns and 5 rows then all the values in a particular row are not repeated for any other row. The search of this type of rows might be required when we have a lot of duplicate rows in our data set. To do this, we can use group_by_all function of dplyr package as shown ...
Read MoreHow to find the row and column index of a character value in an R data frame?
To find the row and column index for a numerical value in an R data frame we use which function and if the value is character then the same function will be used but we need to pass the value appropriately. For example, if we have a data frame called df that contains a value say Data then we can find the row and column index of Data by using the command as which(df=="Data", arr.ind=TRUE).Example1Consider the below data frame −Live Demo> x1 x2 df1 df1Output x1 x2 1 Female 5 2 Female 5 3 Female 6 4 Female ...
Read MoreHow to split month and year from 6-digit numbers in an R data frame column?
Sometimes we get data that is not in the form to proceed with the analysis and one such situation is dates stored in 6-digit numbers as 202105 that represents fifth month of year 2021 instead of date format as 2021/05. Therefore, we need to split the date and extract the month and year from the number. This can be done easily with the help of transform function as shown in the below examples.Example1Consider the below data frame −Live Demo> Date Response1 df1 df1Output Date Response1 1 202103 0.946367628 2 202103 1.241718518 3 202101 -0.657920816 4 202103 -0.809622853 ...
Read MoreHow to filter single column of a matrix with column name in R?
To filter a single column of a matrix in R if the matrix has column names, we can simply use single square brackets but this will result in a vector without the column name. If we want to use the column name then column name or column number needs to be passed with drop=FALSE argument as shown in the below examples.Example1Live Demo> M1 colnames(M1) M1Output V1 V2 V3 V4 [1, ] 0 0 1 0 [2, ] 1 1 1 1 [3, ] 0 0 0 0 [4, ] 0 1 1 0 [5, ] 1 1 1 ...
Read MoreHow to truncate character vector with three dots after n characters in R?
To truncate character vector with three dots after n characters can be done with the help of str_trunc function of stringr package. For example, if we have a character vector say x and each value containing 10 characters then truncating those values with three dots after 5 characters can be done by using the command str_trunc(x, 8).Example1Live Demo> x1 x1Output[1] "rstuvwxyz" "rstuvwxyz" "abcbefgh" "rstuvwxyz" "ijklmnopq" "ijklmnopq" [7] "ijklmnopq" "rstuvwxyz" "rstuvwxyz" "rstuvwxyz" "rstuvwxyz" "abcbefgh" [13] "rstuvwxyz" "abcbefgh" "abcbefgh" "ijklmnopq" "ijklmnopq" "ijklmnopq" [19] "ijklmnopq" "rstuvwxyz" "rstuvwxyz" "abcbefgh" "abcbefgh" "ijklmnopq" [25] "ijklmnopq" "ijklmnopq" "rstuvwxyz" "rstuvwxyz" "rstuvwxyz" "rstuvwxyz" [31] "rstuvwxyz" "abcbefgh" "abcbefgh" "rstuvwxyz" "rstuvwxyz" ...
Read MoreHow to assign a column value in a data frame based on another column in another R data frame?
To assign a column value based on another column, we can use ifelse function. The ifelse function checks whether the value in one column of one data frame matches the value in another column of another data frame by using equal sign (==) and then replace the original value with the new column if there is no match else returns the original value. Check out the below example to understand how it can be done.ExampleConsider the below data frame −Live Demo> x1 x2 df1 df1Output x1 x2 1 3 5 2 3 7 3 ...
Read MoreHow to remove rows in a data.table object with NA's in R?
If a row contains missing values then their sum will not finite, therefore, we can use is.finite function with the data.table object to remove the rows with NA’s. For example, if we have a data.table object called DT that contains some rows with NA’s then the removal of those rows can be done by using DT[is.finite(rowSums(DT))].Example1Loading data.table package and creating a data.table object −> library(data.table) > x1 x2 DT1 DT1Output x1 x2 1: 1 2 2: NA 4 3: 1 2 4: NA 5 5: 1 6 6: 1 8 7: NA 3 8: 1 ...
Read MoreHow to create boxplot with multiple factor levels using ggplot2 in R?
To create a boxplot, we have one factor and one numerical column and the boxplot is created for each category or levels in that factor. Now if we have two factors then the boxplot can be created for both factor levels by passing fill argument in geom_boxplot. This will help us to differentiate between the boxplots for the two factors. Check out the below examples to understand how it works.ExampleConsider the below data frame −Live Demo> x y grp df dfOutput x y grp 1 Female 0.790349405 b ...
Read MoreHow to create a histogram with dots instead of bars in base R?
To create a histogram with dots instead of bars, we can use the plot function in base R. The x values will be based on the sorting of the vector values and the y values will be based on the sequence of the table for the vector values. Therefore, we would be needing sorting and table with sequence. Check out the below examples to understand how it can be done.Example1> x1 plot(sort(x1),sequence(table(x1)))OutputExample2> x2 plot(sort(x2),sequence(table(x2)))Output
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