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Server Side Programming Articles
Page 1124 of 2109
How to select rows of an R data frame that are non-NA?
To select rows of an R data frame that are non-Na, we can use complete.cases function with single square brackets. For example, if we have a data frame called that contains some missing values (NA) then the selection of rows that are non-NA can be done by using the command df[complete.cases(df), ].Example1Consider the below data frame −> x1 x2 x3 df1 df1Output x1 x2 x3 1 1 NA NA 2 NA 5 3 3 1 5 NA 4 1 NA NA 5 NA 5 NA 6 NA 5 3 7 NA 5 NA 8 1 NA ...
Read MoreHow to display the data frame summary in vertical order in R?
To display the data frame summary in vertical order, we can use lapply and cbind function along with the summary function. For example, if we have a data frame called df then the summary of df in vertical order can be found by using the below command −lapply(df, function(x) cbind(summary(x)))Example1Consider the below data frame −> x1 x2 x3 x4 x5 df1 df1Output x1 x2 x3 x4 x5 1 4 0 2 2 6 2 7 2 4 1 7 3 7 2 3 3 6 4 4 0 4 5 2 5 5 2 2 ...
Read MoreHow to create a list of regression models for predefined vectors in R?
To create a list of regression models for predefined vectors, we can create a blank list and then use the for loop to create the list of regression models. For example, if we have two vectors say x and y, and we want to create a list of regression model between x and y then we create a blank list using list() and perform for loop a particular number of times as shown in the below examples.Example1x
Read MoreHow to find the proportion of each value for a cross tab obtained from a data frame in R?
To find the proportion of each value for a cross tab obtained from a data frame, we can use prop.table function. Suppose we have a data frame called df that contains three columns, two categorical say C1 and C2 and one numerical say Y then the cross tab will be created by using the command xtabs(Y~.,df). Now the proportion of each value can be found by using prop.table(xtabs(Y~.,df),1).Example1Consider the below data frame −f1
Read MoreHow to check if a time series is stationary in R?
To check if a time series is stationary, we can use Dickey-Fuller test using adf.test function of tseries package. For example, if we have a time series object say TimeData then to check whether this time series is stationary or not we can use the command adf.test(TimeData).Example1x1
Read MoreHow to apply multiple AND conditions to a data frame in R?
To apply multiple conditions to a data frame, we can use double and sign that is &&. For example, if we have a data frame called df that contains three columns say x, y, z and we want to add a value to all columns if first element in z equals to 5 then it can be done by using the command −if(df$x && df$y && df$y == 5){ df$x = df$x+10 df$y = df$y+10 df$z = df$z+10 }Example1Consider the below data frame −x1
Read MoreHow to find the high leverage values for a regression model in R?
To find the high leverage values for a regression model, we first need to find the predicted values or hat values that can be found by using hatvalues function and then define the condition for high leverage and extract them. For example if we have a regression model say M then the hat values can be found by using the command hatvalues(M), now to find the high leverage values that are greater than 0.05 can be found by using the below code −which(hatvalues(M)>0.05)Example1Consider the below data frame −x1
Read MoreHow to add a variable description in R?
To add a variable description in R, we can use comment function and if we want to have a look at the description then structure call of the data frame will be used. For example, if we have a data frame say df that contains a column x then we can describe x by using the command comment(df$x)
Read MoreHow to convert a list to JSON in R?
To convert a list to JSON, we can use toJSON function of jsonlite package. For example, if we have a list called LIST then it can be converted to a JSON by using the command toJSON(LIST,pretty=TRUE,auto_unbox=TRUE). We need to make sure that the package jsonlite is loaded in R environment otherwise the command won’t work.ExampleList
Read MoreHow to find the object size in R?
To find the object size in R, we can use object.size function. For example, if we have a data frame called df then the size of df can be found by using the command object.size(df). Similarly, if we have a vector say x then it’s size can be found using object.size(x) and for a matrix M it can be object.size(M).Example1Consider the below data frame −x
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