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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to check if a string contains only one type of character in R?
If a string contains more than one character then all of them could be same or different. If we want to check if a string contains only one type of character, then stri_count_fixed function of stringi package will be used with nchar function.Check out the below given examples to understand how it can be done.Example 1Following snippet creates a sample data frame −Countries
Read MoreHow to split a vector into smaller vectors of consecutive values in R?
To split a vector into smaller vectors of consecutive values, we can use split function with cumsum function.For example, if we have a vector called X that contains some consecutive values then we split X into smaller vectors of consecutive values by using the command given below −split(x,cumsum(c(1,diff(x)!=1)))Example 1Following snippet creates a vector −x1
Read MoreHow to find the mean based on single group value in an R data frame?
To find the mean based on single group value in an R data frame, we can use mean function with subsetting through single square brackets.For example, if we have a data frame called df that contains a categorical column say C having three groups Low, Medium, High and a numerical column say Num then mean of Num for Medium group can be found by using the command given below −mean(df$C[df$Num=="Medium"])Example 1Following snippet creates a sample data frame −Group
Read MoreHow to fill a data.table row with missing values in R?
Instead of filling missing values, we sometimes need to replace the data with missing values. This might be required in situations when missing values are coded with a number or the actual values are not useful or sensible for the data study. Also, we might want to replace the values with something else in the future.Check out the below given examples to understand how we can fill data.table row with missing values.Example 1Following snippet creates a data.table object −library(data.table) x1
Read MoreHow to subset matrix row values based on different columns?
Suppose we have a matrix called M that contains three columns and we want to subset row values of M but from different columns that means the subset will not have values only from a single column.Hence, before creating the subset we first need to find the column numbers that can be used for the creation of subset and this can be done with the help of sample function if column numbers are not known. After that we can use cbind function with single square brackets for subsetting.Check out the Examples given below to understand how it can be done.Example ...
Read MoreHow to find the row products for each row in an R matrix?
To find the row products for each row in an R matrix, we can use rowProds function of matrixStats package.For Example, if we have a matrix called MATRIX then we can find the row products for each row in MATRIX by using the command given below −rowProds(MATRIX)Example 1Following snippet creates a sample matrix −M1
Read MoreConvert a numeric column to binary factor based on a condition in R data frame
To convert a numeric column to binary factor based on a condition in R data frame, we can use factor function along with ifelse function.For Example, if we have a data frame called df that contains a numerical column say Num and we want to convert it to a binary factor if Num is less than 100 then it will be Minor otherwise Major then we can use the below given command −df$Num_Factor
Read MoreHow to standardize data.table object column by group in R?
To standardize data.table object column by group, we can use scale function and provide the grouping column with by function.For Example, if we have a data.table object called DT that contains two columns say G and Num where G is a grouping column and Num is a numerical column then we can standardize Num by column G by using the below given command −DT[,"Num":=as.vector(scale(Num)),by=G]Example 1Consider the below data.table object −library(data.table) Grp
Read MoreReplace each value in a column with the largest value based on a condition in R data frame.
Suppose we have three columns say X, Y, and Z in an R data frame called df and we want to replace values in columns X and Y with the same value if the values are greater than values in Z and if they are less than the values in Z then we can replace with Z values.Check out the below Examples to understand how it can be done.Example 1Following snippet creates a sample data frame −x1
Read MoreHow to randomly replace values in an R data frame column?
The random replacement values in an R data frame column can be done with the help of sample function along with nrow function and single square subsetting.For Example, if we have a data frame called df that contains a columns say X and we want to randomly replace 5 values in X with 1.5 then we can use the below given command −df$X[sample(nrow(df),5)]
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