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Articles by Nizamuddin Siddiqui
Page 46 of 196
How 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 −> x1 x2 df1 df1Output x1 x2 1 Female 5 2 Female 5 3 Female 6 4 Female 6 ...
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 −> Date Response1 df1 df1Output Date Response1 1 202103 0.946367628 2 202103 1.241718518 3 202101 -0.657920816 4 202103 -0.809622853 5 ...
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.Example1> 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 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).Example1> 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" "abcbefgh" ...
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 −> x1 x2 df1 df1Output x1 x2 1 3 5 2 3 7 3 0 ...
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 −> x y grp df dfOutput x y grp 1 Female 0.790349405 b 2 ...
Read MoreHow to display average line for y variable using ggplot2 in R?
To display the average line for y variable using ggplot2, we can use geom_hline function along with the yintercept. In the yintercept, we would need to calculate the mean of the y variable and we can also change the colour of the line using color argument inside the geom_hline function.ExampleConsider the below data frame −> x y df dfOutputx y 1 -1.07323904 0.368641641 2 0.92531148 -0.196530651 3 -0.57433739 0.710957804 4 1.17367100 0.300110517 5 0.00769624 -1.287517035 6 0.64901161 -0.476105351 7 0.70197701 -0.683592585 8 -0.80807441 -1.716264317 9 0.10827026 0.116964308 10 -1.10451308 0.660382307 11 -0.01612692 -1.182533283 12 2.20292198 -1.890223763 13 -1.03368161 -0.526983486 14 ...
Read MoreHow to subset a data frame based on a vector values in R?
If we have a vector and a data frame, and the data frame has a column that contains the values similar as in the vector then we can create a subset of the data frame based on that vector. This can be done with the help of single square brackets and %in% operator. The %in% operator will help us to find the values in the data frame column that matches with the vector values. Check out the below examples to understand how it works.Example1Consider the below data frame df1 and vector v1 −> x1 x2 df1 df1Outputx1 x2 1 2 ...
Read MoreHow to check if a data frame column contains duplicate values in R?
To check if a data frame column contains duplicate values, we can use duplicated function along with any. For example, if we have a data frame called df that contains a column ID then we can check whether ID contains duplicate values or not by using the command −any(duplicated(df$ID))Example1Consider the below data frame −ID
Read MoreHow to sort each row of an R data frame in increasing order?
To sort each row of an R data frame in increasing order, we can use apply function for sorting the columns and then transpose the output. For example, if we have a data frame called df that contains 5 columns then each row of df can be sorted in increasing order by using the command t(apply(df,1,sort)).Example1Consider the below data frame −x1
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