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Data Manipulation and Transformation Tutorials

How to Use match() Function in R

  • R-PROGRAMMING
The match() function used to find first position of element in a vector,list or data frame in R. The following method shows how you can do it with syntax. Method: Use match() Function match(x,list) x: The element whose position want to find. The following example shows how to use match() function in R: Use match() Function to Find Position of Element from Vector Let’s see how we can find element position from vector using match() function:
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How to Use the cat() Function in R to Concatenate Objects

  • R-PROGRAMMING
The cat() function to concatenate or merge objects in R. The following method shows how you can do it with syntax. Method: Use cat() Function cat(value1,value2,..., file = "file_name", sep = " ", append = FALSE) Here we pass values,file name in which store values,seperated by symbol and append is used to whether to append output to existing file or create new file. The following examples show how to use cat() function in R.
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How to Use the duplicated Function in R

  • R-PROGRAMMING
The duplicated() function in R is used to get duplicate values in vector or data frame. The following method shows how to use duplicated function in R with syntax. Method: Use duplicated() Function dataframe[duplicated(dataframe$column name), ] The following example shows how to use this method with example. First create data frame which having duplicate rows in it: # Define data frame df <- data.frame(Machine_name=c("A","B","C","D","A","A","G","B"), Temperature=c(12,9,14,13,18,28,22,23), Pressure=c(20,25,27,29,30,32,39,40)) # Print data frame print(df) Output:
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How to Use the identical() Function in R

  • R-PROGRAMMING
The identical() function is used compare two object and check whether they are identical or not.This function gives output in boolean value means it gives TRUE when two objects are identical and it gives FALSE when two objects are not identical. The following method show how you can do it with syntax. Method: Use identical() Function identical(object1,object2) The following example shows how to use identical() function in R. Use identical() to Check if Two Strings are Identical or Not Let’s see how we can comapre two string and check they are equal or not:
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How to Use the intersect() Function in R

  • R-PROGRAMMING
To fnd common elements between two vector or object, you can use intersect() function in R. The following method shows how you can do it with syntax. Method: Use intersect() Function intersect(object1,object2) Let’s understood this syntax using example: Use intersect() Function For Vectors Let’s create two vectors and apply intersect() function on them: # Define vector Temp1=c(77,"A",89,78,"C",84,81,74,"B") Temp2=c(77,85,"A",77,78,"D",75,74,"B") # Use intersect function i <- intersect(Temp1,Temp2) # Show common values print(i) Output:
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How to Use the melt() Function in R

  • R-PROGRAMMING
The melt() function from reshape package is used to convert data frame into wide format to long format in R. A long format data frame repeat values from first column and in wide format data frame does not repeat values from first column. The following method shows how you can do it with syntax. Method: Use melt() Function library(reshape) melt(dataframe,id="column_name") The following example shows how to use melt() function in R.
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Concatenate Column Values into a New Column in R Data Frame

  • R-PROGRAMMING
To concatenate column values into new column in R, you can use two different function i.e. paste() function and unite() function. The following methods show how you can use it with syntax. Method 1: Use paste() Function paste(df$column1, df$column2, df$column3,..... , sep = "_") Method 2: Use unite() Function unite(df, new_column, column1, column2, column3,...., sep = "_") Let’s create data frame first to apply this function on it: # Create data frame df <- data.
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Convert Character to Integer Column in R Data Frame

  • R-PROGRAMMING
To convert character to integer column in R, you can use as.integer() or as.numeric() function. The following methods show how you can do it with syntax. Method 1: Use as.intger() Function as.integer(df$column_name) Method 2: Use as.numeric() Function as.numeric(df$column_name) The following examples show how you can use these methods. Let’s first create data frame and also check datatype of each column of data frame. # Create data frame df <- data.frame(Start_date=as.Date(c("2000-05-21","2000-05-22","2000-05-23","2000-05-24","2000-05-25","2000-05-26")), Machine_name = c("Machine1","Machine2","Machine1","Machine3","Machine2","Machine3"), Value = c("108","120","135","95","98","105"),Reading= c(110,97,91,89,80,85)) # Print data frame print(df) # print datatype print(str(df)) Output:
3 min Read 1

Create data frame in R

  • R-PROGRAMMING
To create data frame in R langauge, you can use data.frame() function. The following method shows how you can do it with syntax. Method: Use data.frame() Function data.frame(column_name = c(value1,value2,...)) Here c represents column. The following examples shows how to create data frame in R. Create Data Frame Using data.frame() Function in R Here we see example to create data frame which having machine data: # Create data frame df <- data.
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How to Add Multiple Columns to Data Frame in R

  • R-PROGRAMMING
In R, you can use the following methods to add multiple columns to a data frame in R. Method 1: Add Multiple Columns to data.frame Object df[c('new_col1', 'new_col2', 'new_col3',..)] <- NA Method 2: Add Multiple Column to data.table object library(data.table) df[ , ':='(new_col1 = new_col1, new_col2 = new_col2, new_col3 = new_col3,...)] The following examples shows how to add multiple columns to data frame. How to Add Multiple Columns to data.frame Object Suppose you have data frame already created and you want to add multiple columns to it.
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