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Data Manipulation and Transformation Tutorials

How to Use str() Function in R

  • R-PROGRAMMING
The str() function in R is used to display internal structure of an R object. The following method shows how you can do it with syntax. Method 1: Use str() Function str(object) The following example shows how to use str() function in R. Apply str() Function on Vector Let’s see how we can check internal structure of an array using str() function: # Create vector x=c(78,89,85,84,81,79,77,85,77,78,75,74,71,79,76,78) # Show vector print(x) # Display internal structure of vector str(x) Output:
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How to Use strsplit() Function in R to Split Elements of String

  • R-PROGRAMMING
There is strsplit() function in R used to split element in string with specified delimiter. The following method shows how you can do it with syntax. Method 1: Use strsplit() Function strsplit(string, pattern) The following example shows how to use strsplit() function in R: Apply strsplit() Function on Character Vector Let’s see how we can split character vector using strsplit() function based on comma: # Split string based on spaces str <- "R, Python, Java, C++, Ruby" # Split string split_str <- strsplit(str,",") # Show output print(split_str) # Check class of string class(split_str) Output:
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How to Use substring Function in R

  • R-PROGRAMMING
The substring() function is used to extract substrings in a character vector. The following method shows how you can do it with syntax. Method 1: Use substring() Function substring(data,first=x,last=y) data : A character vector x : Starting position of the substring y: Ending position of the substring The following example shows how to use substring() method. Get Substring Using substring() Function We can use following example to get substring from character vector using substring() function:
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How to Use sum() Function in R

  • R-PROGRAMMING
The sum() function used to calculate sum of a numeric vector, list or data frame. The following method shows how you can do it with syntax. Method 1: Use sum() Function sum(vector.na.rm=TRUE) The following example shows how to use sum() function in R. Use sum() Function to Sum Values in Vector Let’s see how we can calculate sum of values in vector: # Define vector vector1 <-c(20,25,27,29,30,32,39,40) # Find sum of vector values sum(vector1) Output:
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How to Use text() Function in R to Add Text to Plot

  • R-PROGRAMMING
The text() function is used to add text to plot in R. The following method shows how you can do it with syntax. Method 1: Use text() Function text(x=x, y=y, labels="Text") The following example shows how to use text() function in R to add text to plot. Using text() Function Let’s see how to use text() function in R: # Create dataframe df <- data.frame(Machine_name=c("A","B","C","D","E","F","G","H"), Temperature=c(12,9,14,13,18,28,22,23), Pressure=c(20,25,27,29,30,32,39,40)) # Create scatterplot plot(df$Temperature,df$Pressure) # Add text in plot text(x=20,y=35,"This is scatter plot") Here the above snippet shows scatter chart along with text added to it.
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How to Use the cast() Function in R

  • R-PROGRAMMING
The cast() function from reshape2 package is used to reshape dataframes. This cast() function convert dataframe from long format to wide format. The wide format having values that does not repeat in first column and long format contains values that contain repeat values in first column. The following method shows how you can do it with syntax. Method 1: Use cast() Function library(reshape2) cast(df, column1 ~ column2) The following example shows how to use cast() function in R.
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How to Use the dim() Function in R

  • R-PROGRAMMING
The dim() function is used to get dimension of data frame, matrix or array in R. The following method shows how you can do it with syntax. Method: Use dim() Function dim(dataframe) The following example shows how you can use the dim() function in R. Use dim() Function to Get Dimension of Data Frame Let’s apply dim() function on data frame: # Create data frame df <- data.frame(Machine_name=c("A","B","C","D","E","F"), Pressure=c(78.2, 71.7, 80.
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How to Use the dist Function in R

  • R-PROGRAMMING
The dist() function is used to calculate distance matrix which shows distance between rows of matrix or dataframe. The following method shows how you can do it with syntax. Method 1: Use dist() Function dist(matrix) The following example shows how to use dist() function in R. Using dist() Function Let’s see how we can use dist() function to calculate distance matrix in R: # Define vectors a <-c(78,85,89,96,74,75) b <-c(65,66,64,69,70,61) c <-c(23,25,26,19,21,18) d <-c(45,41,35,36,39,48) # Define matrix matrix1 <- rbind(a,b,c,d) # Show matrix print(matrix1) # Calculate distance matrix dist(matrix1) [,1] [,2] [,3] [,4] [,5] [,6] a 78 85 89 96 74 75 b 65 66 64 69 70 61 c 23 25 26 19 21 18 d 45 41 35 36 39 48 a b c b 45.
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How to Use the get() Function in R to Retrieve Named Objects

  • R-PROGRAMMING
You can use get() function to get named objects. The following methods show how you can do it with syntax. Method 1: Use get() Function get("object_name") Method 2: Use get0() Function The get0() function is used to get named object if not found then show custom message. get0("object_name",ifnotfound="custom message") Method 3: Use mget() Function The mget() function to get multiple objects. mget(c("object1","object2","object3",..)) Here is few examples to understand this function in detailed:
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How to Use the scan() Function in R

  • R-PROGRAMMING
The scan() function is used to read data from file in vector or list format in R. The following method shows how you can do it with syntax. Method 1: Use scan() Function scan(file="name_of_file",what=type_of_data_to_read) The following example shows how to use scan() function in R. Use scan() function Suppose I have Machine_data.csv file in my working directory and want to read data from file in list format: # Read from CSV file into list format data <- scan("Machine_data.
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How to Use the sink() Function in R

  • R-PROGRAMMING
In R language you can export string values or dataframes in text and CSV file. For this you can use sink() function to create external connection. The following method shows how you can do it with syntax. Method: Use sink() Function sink("file_name.txt") sink() The following example shows how to use this function: Use sink() Function to Export String to Text File Let’s see how we can use sink() function to export string to text file:
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How to Use unlist() Function in R

  • R-PROGRAMMING
In R you can use unlist() function for convert list to a vector. The following method shows how you can do it with syntax. Method 1: Use unlist() Function unlist(list_name) Let’s first create list with numeic values: # Create list lst <- list(A=c(12.39,11.25,12.15,13.48,13.78),B=c(78,89,85,84,81),C=c(5,7,1,2,7)) # Print list print(lst) Output: $A [1] 12.39 11.25 12.15 13.48 13.78 $B [1] 78 89 85 84 81 $C [1] 5 7 1 2 7 The output shows list with numeric values.
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