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Articles by Nizamuddin Siddiqui
Page 33 of 196
How to perform one sample Kolmogorov-Smirnov test in R?
The one sample Kolmogorov-Smirnov test is used to check whether a data set follows certain distribution of not.For Example, if we have a vector called X and we want to know whether values in X follow normal distribution or not then we can use the command given below −ks.test(X,"pnorm")Check out the below Examples to understand how it works.Example 1Following snippet creates a sample data frame −x1
Read MoreHow to increase the distance between boxplots using ggplot2 in R?
To increase the distance between boxplots created by using ggplot2, we can reduce the widths of the boxplots and hence the distance between the plots will be automatically increased. This will be required when we have large number of categories for which the boxplots are created.Check out the below given example to understand how it can be done.ExampleFollowing snippet creates a sample data frame −Group
Read MoreHow to set lower triangular matrices including main diagonal to zero stored in an R array?
The matrices stored in an array cannot directly have zero at lower triangular or upper triangular positions because assignment in arrays is not straight forward. Therefore, to set lower triangular matrices to zero stored in an R array, we can use for loop.Check out the below given example to understand how it can be done.ExampleFollowing snippet creates a sample array −Array
Read MoreHow to combine list elements of different sizes in R?
To combine list elements of different sizes in R, we can use expand.grid function. For Example, if we have a list called LIST that contains elements of different sizes then we can combine those items by using the command given below −expand.grid(LIST)Example 1To combine list elements of different sizes in R, use the following snippet −List1
Read MoreHow to display X-axis labels with dash in base R plot?
To display X-axis labels with dash in base R plot, we can use axis function and define the labels manually. For this purpose, we can first create the plot without X-axis labels by using the argument xaxt="n" and then use the axis function.Check out the below example to understand how it can be done.ExampleIn order to display X-axis labels with dash in base R plot, use the following code −plot(5, 5)OutputIf you execute all the above given codes as a single program, it generates the following output −In order to display X-axis labels with dash in base R plot, add ...
Read MoreHow to find the groupwise cumulative mean in R?
To find the groupwise cumulative mean, we can use cummean function of dplyr package.For example, if we have a data frame called df that contains a categorical column say Group and a numerical column say Response then the groupwise cumulative mean can be found by using the command given below −df%>%group_by(Group)%>%mutate(CM=cummean(Response))Example 1Following snippet creates a sample data frame −Group
Read MoreHow to combine data frames stored in a list in R?
To combine data frames stored in a list in R, we can use full_join function of dplyr package inside Reduce function.For Example, if we have a list called LIST that contains some data frames then we can combine those data frames by using the below command −Reduce(full_join,LIST)Check out the Example given below to understand the Output of this command.ExampleFollowing snippet creates a sample data frame −df1
Read MoreHow to create barplot for some top values in an R data frame?
To create barplot for some top values in an R data frame, we can subset the required top values inside the barplot function.For example, if we have a data frame called df that contains a categorical column say C and a numerical column for frequency defined as F then the barplot for top five values can be created by using the below mentioned command −barplot(df$F[1:5],names.arg=df$C[1:5])ExampleFollowing snippet creates a sample data frame −Category
Read MoreFind the column name of least value in each row of an R dataframe.
To find the column name that has the least value for each row in an R data frame, we can use colnames function along with apply function.For Example, if we have a data frame called df then we can find column name that has the least value for each row by using the command mentioned below −df$Least_Column
Read MoreHow to set the coefficient of one variable to 1 for logistic regression model in R?\\n
To set the coefficient of one variable to 1 for logistic regression model, we can use offset function.For example, if we have a data frame called df that contains a binary column say y and three independent variables say x1, x2, and x3 and we want to create a logistic regression model with x1 coefficient equal to 1 then we can use the below given command −glm(y~x2+x3,offset=x1,data=df,family=binomial)Example 1Following snippet creates a sample data frame −y1
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