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R Programming Articles
Page 138 of 174
How to find the quartile for each value in an R vector?
Any numerical data can be divided into four parts (four quarters) by using three quartiles, first quartile at 25%, second quartile at 50% and third quartile at 75% hence there will be four quarters to represent first 25%, second 25%, third 25% and the last 25% in a set of data.If we want to find the quartile (1 to 4) for each value in an R data frame column then we can use the quantile function and cut function as shown in the Examples given below.Example 1Following snippet creates a sample data frame −x
Read MoreHow to match and replace column names stored in R data frames in R-Programming?
If we have a data frame that contains a column of column names which matches with the column names of a data frame and another column that has different values then we can set these different values as the new column names of the data frame having matched column names.This can be done with the help of match function. Check out the below Examples to understand how it works.Example 1Following snippet creates a sample data frame −x1
Read MoreConvert a data frame with grouping column into a list based on groups in R.
To convert a data frame with grouping column into a list based on groups, we can use split function.For Example, if we have a data frame called df that contains a categorical column say Group and a numerical column say DV then we can convert df into a list based on groups in Group column by using the command as mentioned below −split(df$DV,df1$Group).Example 1Following snippet creates a sample data frame −Group
Read MoreDefine column and row names of a square matrix in a single line code if they are same in R.
If we have a square matrix or we want to create a square matrix and the row names and column names for this matrix are same then we can define these names in a single line of code.For Example, if we have a matrix called M that has 10 rows and 10 columns that has first ten alphabets as row and column names then we can define the column names as colnames(M)
Read MoreHow to subset non-duplicate values from an R data frame column?
Generally, the duplicate values are considered after first occurrence but the first occurrence of a value is also a duplicate of the remaining. Therefore, we might want to exclude that as well.The subsetting of non-duplicate values from an R data frame column can be easily done with the help of duplicated function with negation operator as shown in the below Examples.Example 1Following snippet creates a sample data frame −x
Read MoreCreate a data.table object of combination of correlation coefficients.
To create a data.table object of combination of correlation coefficients, we first need to find the correlation matrix then the combination of variables for which the correlation matrix is created then data.table will be used to combine the combination of variables and the correlation coefficients.Check out the below Examples to understand how it can be done.Example 1Following snippet creates a sample data frame −x1
Read MoreSelect columns of an R data frame and skip if does not exist.
Sometimes we have a large number of columns in the data frame and we know the name of some columns but among known ones some does not exist in the data frame. Now if we want to select the columns that we know and skip the ones that do not exist then we can use the subsetting.For Example, if we have a data frame called df that contains twenty columns and we believe that x, y, z exists in df but z is not there in reality. Now the selection of columns x, y, z that will skip z can ...
Read MoreHow to divide columns of a matrix by vector elements in R?
Suppose we have a vector say V that contains five elements and a matrix say M that has five columns. Now again, suppose that we want to divide each column in M by corresponding value in vector V, which means first column in M will be divided by first value in the V and so on then we can use the sweep function as shown below −sweep(M,2,V,FUN="/")Example 1Consider the below matrix and vector −M1
Read MoreHow to create a time series plot in R without time vector?
To create a time series plot in R without time vector, we can use ts.plot function.For Example, if we have a vector called X then we can create the time series plot of X by using the command ts.plot(X), the Output of this command will have a time axis in place of X-axis. Check out the below Examples to understand how it works.Example 1Consider the following vector −x
Read MoreHow to create vertical line in xyplot in R?
To create vertical line in xyplot, we can use abline function.For Example, if we have a data frame called df that contains two columns say X and Y and we want to create a scatterplot between X and Y using xyplot with a vertical line at X = 2 then we can use the below command −xyplot(y~x,df,abline=c(v=2))ExampleConsider the data frame given below −x
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