# --1-Conditionals and Control Flow ### #1-Relational Operators ​[Relational operators video](https://www.youtube.com/watch?v=ZJ7H-3j_-mE)​ ### #2-Equality * In the editor on the right, write R code to see if `TRUE` equals `FALSE`. * Likewise, check if `-6 * 14` is *not* equal to `17 - 101`. * Next up: comparison of character strings. Ask R whether the strings "useR" and "user" are equal. * Finally, find out what happens if you compare logicals to numerics: are `TRUE` and 1 equal? ```r # Comparison of logicals TRUE==FALSE ​ # Comparison of numerics -6*14 != 17-101 ​ # Comparison of character strings 'useR'=='user' ​ # Compare a logical with a numeric TRUE==1 ``` ### #3-Greater and less than Write R expressions to check whether: * `-6 * 5 + 2` is greater than or equal to `-10 + 1`. * "raining" is less than or equal to "raining dogs". * TRUE is greater than FALSE. ```r # Comparison of numerics -6*5+2>=-10+1 # Comparison of character strings 'raining'<='raining dogs' # Comparison of logicals TRUE>FALSE ``` ### #4-Compare vectors Using relational operators, find a logical answer, i.e. TRUE or FALSE, for the following questions: On which days did the number of LinkedIn profile views exceed 15? When was your LinkedIn profile viewed only 5 times or fewer? When was your LinkedIn profile visited more often than your Facebook profile? ```r # The linkedin and facebook vectors have #already been created for you linkedin <- c(16, 9, 13, 5, 2, 17, 14) facebook <- c(17, 7, 5, 16, 8, 13, 14) # Popular days linkedin>15 # Quiet days linkedin<=5 # LinkedIn more popular than Facebook linkedin>facebook ``` ### #5-Compare matrices Using the relational operators you've learned so far, try to discover the following: When were the views exactly equal to 13? Use the views matrix to return a logical matrix. For which days were the number of views less than or equal to 14? Again, have R return a logical matrix. ```r # The social data has been created for you linkedin <- c(16, 9, 13, 5, 2, 17, 14) facebook <- c(17, 7, 5, 16, 8, 13, 14) views <- matrix(c(linkedin, facebook), nrow = 2, byrow = TRUE) print(views) # When does views equal 13? views==13 # When is views less than or equal to 14? views<=14 ``` ### #6-Logical Operators ​[Logical operators video](https://www.youtube.com/watch?v=6PpQS-YLWDQ) ​ ### #7-& and | (AND & OR) ```r #Write R expressions to solve the following #questions concerning the variable last: #Is last under 5 or above 10? #Is last between 15 and 20, excluding 15 but including 20? # The linkedin and last variable are already defined for you linkedin <- c(16, 9, 13, 5, 2, 17, 14) last <- tail(linkedin, 1) # Is last under 5 or above 10? last<5 | last>10 # Is last between 15 (exclusive) and 20 (inclusive)? last>15 & last<=20 ``` ### #8-& and | (AND & OR) (2) ```r #When did LinkedIn views exceed 10 and did Facebook views- #fail to reach 10 for a particular day? #Use the linkedin and facebook vectors. #When were one or both of your LinkedIn #and Facebook profiles- #visited at least 12 times? #When is the views matrix equal to a number #between 11 and 14, #excluding 11 and including 14? linkedin <- c(16, 9, 13, 5, 2, 17, 14) facebook <- c(17, 7, 5, 16, 8, 13, 14) views <- matrix(c(linkedin, facebook), nrow = 2, byrow = TRUE) # The social data (linkedin, facebook, views) #has been created for you # linkedin exceeds 10 but facebook below 10 linkedin>10 & facebook<10 # When were one or both visited at least 12 times? linkedin>=12 | facebook>=12 # When is views between 11 (exclusive) and 14 (inclusive)? views>11 & views<=14 ``` ### #9-Reverse the result: ! ```r x <- 5 y <- 7 !(!(x < 4) & !!!(y > 12)) ``` ### #10-Blend it all together ```r #Select the entire second column, named day2, #from the li_df data frame #as a vector and assign it to second. #Use second to create a logical vector, that contains TRUE #if the corresponding number of views is strictly #greater than 25 #or strictly lower than 5 and FALSE otherwise. #Store this logical vector as extremes. #Use sum() on the extremes vector to calculate #the number of TRUEs in #extremes (i.e. to calculate the number of #employees that are #either very popular or very low-profile). #Simply print this number to the console. employee<-c("employee_1","employee_2","employee_3", "employee_4","employee_5") day1<-c(2,19,24,22,25) day2<-c(3,23,18,18,25) li_df<-data.frame(employee,day1,day2) # li_df is pre-loaded in your workspace li_df # Select the second column, named day2, from li_df: second second<-li_df$day2 second # Build a logical vector, TRUE if value in second #is extreme: extremes extremes<-second>25 | second<5 extremes # Count the number of TRUEs in extremes sum(extremes) # Solve it with a one-liner sum(li_df$day2 > 25 | li_df$day2 < 5) ``` ### #11-Conditional Statements ​[How to use conditional statements in r](https://www.youtube.com/watch?v=qvSKipqzg3U)​ ### #12-The if statement ```r #Examine the if statement that prints out #"Showing LinkedIn information" #if the medium variable equals "LinkedIn". #Code an if statement that prints "You're popular!" #to the console if the num_views variable exceeds 15. # Variables related to your last day of recordings medium <- "LinkedIn" num_views <- 14 # Examine the if statement for medium if (medium == "LinkedIn") { print("Showing LinkedIn information") } # Write the if statement for num_views if (num_views>15){ print("You're popular!") } ``` ### #13-Add an else ```r #Add an else statement to both control structures, such that #"Unknown medium" gets printed out to the console when the #if-condition on medium does not hold. #R prints out "Try to be more visible!" #when the if-condition on num_views is not met. # Variables related to your last day of recordings medium <- "LinkedIn" num_views <- 14 # Control structure for medium if (medium == "LinkedIn") { print("Showing LinkedIn information") } else{ print("Unknown medium") } # Control structure for num_views if (num_views > 15) { print("You're popular!") } else{ print("Try to be more visible!") } ``` ### #14-Customize further: else if ```r #Add code to both control structures such that: #R prints out "Showing Facebook information" #if medium is equal to "Facebook". Remember that #R is case sensitive! #"Your number of views is average" is printed if num_views #is between 15 (inclusive) and 10 (exclusive). #Feel free to change the variables medium and num_views #to see how the control structure respond. #In both cases, the existing code should be extended #in the else if statement. #No existing code should be modified. # Variables related to your last day of recordings medium <- "LinkedIn" num_views <- 14 # Control structure for medium if (medium == "LinkedIn") { print("Showing LinkedIn information") } else if (medium == "Facebook") { # Add code to print correct string when condition is TRUE print("Showing Facebook information") } else { print("Unknown medium") } # Control structure for num_views if (num_views > 15) { print("You're popular!") } else if (num_views <= 15 & num_views > 10) { # Add code to print correct string when condition is TRUE print("Your number of views is average") } else { print("Try to be more visible!") } ``` ### #15-Else if (2) ```r if (number < 10) { if (number < 5) { result <- "extra small" } else { result <- "small" } } else if (number < 100) { result <- "medium" } else { result <- "large" } print(result) #Have a look at the following statements: #1-If number is set to 6, "small" gets #printed to the console. #2-If number is set to 100, R prints out "medium". #3-If number is set to 4, "extra small" gets printed #out to the console. #4-If number is set to 2500, R will generate an error, #as result will not be defined. #Select the option that lists all the true statements. #Answer: 1 and 3 ``` ### #15-Else if (3) ```r #Finish the control-flow construct with the #following behavior: #If both li and fb are 15 or higher, set sms equal #to double the sum of li and fb. #If both li and fb are strictly below 10, set #sms equal to half the sum of li and fb. #In all other cases, set sms equal to li + fb. #Finally, print the resulting sms variable to the console. # Variables related to your last day of recordings li <- 15 fb <- 9 # Code the control-flow construct if (li>15 & fb>15) { sms <- 2 * (li + fb) } else if (li<10 & fb<10) { sms <- 0.5 * (li + fb) } else { sms <- li+fb } # Print the resulting sms to the console sms ``` --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. 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