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Articles by Nizamuddin Siddiqui
Page 93 of 196
How to create a scatterplot using five vectors in a single plot window without separating the plots in R?
To create more than one scatterplot in a single plot window we should create the scatterplot for first vector and then add the point of the remaining vectors by using points function and they can be displayed with different colors so that it becomes easy to differentiate among the points of the vectors.ExampleConsider the below vectors −x1
Read MoreHow to remove outliers from multiple boxplots created with the help of boxplot function for columns of a data frame using single line code in R?
A data frame can have multiple numerical columns and we can create boxplot for each of the columns just by using boxplot function with data frame name but if we want to exclude outliers then outline argument can be used. For example, if we have a data frame df with multiple numerical columns that contain outlying values then the boxplot without outliers can be created as boxplot(df,outline=FALSE).ExampleConsider the below data frame:set.seed(151) x1
Read MoreHow to find the confidence interval for the predictive value using regression model in R?
The confidence interval for the predictive value using regression model can be found with the help of predict function, we just need to use interval argument for confidence and the appropriate level for that. For example, if we have a model M and the data frame for the values of independent variable is named as newdata then we can use the following syntax for the confidence interval −predict(M,newdata,se.fit=TRUE,interval="confidence",level=0.95)ExampleConsider the below data frame −set.seed(1234) x1
Read MoreHow to remove a column from a data frame that contains same value in R?
If we have only one value in all of the rows of an R data frame then we might want to remove the whole column because the effect of that column will not make any sense in the data analysis objectives. Thus, instead of removing the column we can extract the columns that contains different values.Exampleset.seed(1001) x1
Read MoreHow to find the median of all columns in an R data frame?
The median is the value in a vector that divide the data into two equal parts. To find the median of all columns, we can use apply function. For example, if we have a data frame df that contains numerical columns then the median for all the columns can be calculated as apply(df,2,median).ExampleConsider the below data frame −set.seed(7) x1
Read MoreHow to find the maximum value for each column of a matrix in R?
To find the maximum value for each column of a matrix, we need to use apply function. For example, if we have a matrix M that contains 2 rows and 2 columns with values 1, 2 in the first row and 3, 4 in the second row then the maximum for each of the columns in that matrix can be found by using the syntax; apply(M,2,max), hence the result will be 3, 4.ExampleM1−-matrix(1:36,ncol=6) M1Output [,1] [,2] [,3] [,4] [,5] [,6] [1,] 1 7 13 19 25 31 [2,] 2 8 14 20 26 32 [3,] 3 9 15 21 27 33 [4,] 4 10 16 22 28 34 [5,] 5 11 17 23 29 35 [6,] 6 12 18 24 30 36Exampleapply(M1,2,max)Output[1] 6 12 18 24 30 36ExampleM2
Read MoreHow to find the frequency of NA values per row in an R data frame?
Since column represent variables, we often find missing values in the columns of a data frame but we may want to find missing values(NA) for cases as well so that we can replace them based on case characteristic instead of the distribution of the variable. In R, we can use rowSums with apply function.ExampleConsider the below data frame −set.seed(8) x1
Read MoreHow to create histogram of all columns in an R data frame?
To create histogram of all columns in an R data frame, we can use hist.data.frame function of Hmisc package. For example, if we have a data frame df that contains five columns then the histogram for all the columns can be created by using a single line code as hist.data.frame(df).ExampleConsider the below data frame −set.seed(9) x1
Read MoreHow to sort a list that contains single sub-elements in decreasing order in R?
Just like a list can have multiple elements, the elements of the list can have multiple sub-elements and the size of those elements may vary as well hence a list with single sub-elements is also possible. If we have such type of list then we can sort that list in decreasing order by using order function but we also need to unlist those elements.ExampleConsider the below list −x1
Read MoreHow to find the frequency of repeated and unique values in a vector in R?
If we unique values in a vector in R and they are repeated then we can find the frequency of those unique values, this will help us to understand the distribution of the values in the vector. On the basis of that distribution analysis, we can proceed with the further analysis that could be used. This can be done with the help of rle function.Examplex1
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