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Articles by Nizamuddin Siddiqui
Page 45 of 196
Find the frequency of exclusive group combinations based on multiple categorical columns in R.
To find the frequency of exclusive group combinations in an R data frame, we can use count function of dplyr package along with ungroup function.For Example, if we have a data frame called df that contains four grouping columns say Grp1, Grp2, Grp3, and Grp4 then we can count the unique group combinations in df by using the below command −count(df,Grp1,Grp2,Grp3,Grp4)%%ungroup()Example 1Following snippet creates a sample data frame −Class1
Read MoreHow to display superscript for X-axis title in base R plot?
To display superscript for X-axis title in base R plot, we can use ^ sign inside mtext function before defining the plain text.For example, if we want to display X2 at position 5 on X-axis then it can be done by using the below command −mtext(expression(paste(plain("X")^plain("2"))), side=1, line=2, at=5, cex=1.2)ExampleConsider the following snippet −plot(1:10) OutputIf you execute the above given snippet, it generates the following Output −To display superscript for X-axis title in base R plot, add the following code to the above snippet −Exampleplot(1:10, xlab="")OutputIf you execute all the above given snippets as a single program, it generates the ...
Read MoreHow to change the order of independent variables for regression summary output in R?
To change the order of independent variables in regression Output, we can pass the variables in the sequence we want while creating the regression model.For example, if we want to have three independent variables and we want to display first at the last position then it can be done as follows −lm(DP1~ ind_var_3+ ind_var_2+ind_var_1,data=”data_frame_name”)ExampleFollowing snippet creates a sample dataframe −iv1
Read MoreHow to check matrix values equality with a vector values in R?
If we have a vector called V that contains five values and a matrix say M that contains five columns and we want to check whether first value in the vector is present in the first column of each row in the matrix and so on for each value in the vector then we can use the below command −t(t(M)==V)Example 1Consider the below matrix and vector −M1
Read MoreFind the row means for columns starting with a string in an R data frame.
To find the row means for columns starting with specific string in an R data frame, we can use mutate function of dplyr package along with rowMeans function.For Example, if we have a data frame called df that contains three columns say x1_x2, x1_x3, x1_x2 and we want to find the row means for columns x1_x2 and x1_x3 then, we can use the below command −df%%mutate(X1_Cmbn=select(.,starts_with("x1_")) %% rowMeans())Example 1Following snippet creates a sample data frame −Grp1_x
Read MoreFind the column and row names in the R data frame based on condition.
To find the column names and row names in an R data frame based on a condition, we can use row.names and colnames function. The condition for which we want to find the row names and column names can be defined inside these functions as shown in the below Examples.Example 1Following snippet creates a sample data frame −x1
Read MoreHow to find the groupwise order of values in an R data frame?
To find the groupwise order of values in an R data frame, we can use mutate function of dplyr package along with rank function and grouping will be done with the help of group_by function.For Example, if we have a data frame called df that contains two columns say Group and DV then we can find the groupwise order of DV values by using the command given below −df%%group_by(Group)%%mutate(Order=rank(DV))Example 1Following snippet creates a sample data frame −Group
Read MoreExtract columns with a string in column name of an R data frame.
To extract columns with a particular string in column name of an R data frame, we can use grepl function for column names and then subset the data frame with single square brackets.For Example, if we have a data frame called df and we want to extract columns that has X in their names then we can use the command mentioned below −df[grepl("X",colnames(df))]Example 1Following snippet creates a sample data frame −Students_Score
Read MoreHow to replace 0 with NA in an R matrix?
To replace 0 with NA in an R matrix, we can use subsetting with single square brackets and then set zeros to NA.For Example, if we have a matrix called M that contains some zeros then we can replace 0 with NA by using the command mentioned below −M[M==0]
Read MoreFind the column number with largest value for each row in an R matrix.
To check which column has the largest value for each row in an R matrix, we can use apply function.For Example, if we have a matrix called M then we can find column that has the largest value for each row by using the command given below −apply(M,1,which.max)Example 1Consider the matrix given below −M1
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