8,9,14

Question 1

expression to say: is not equal to…

Answer 1

!=

Question 2

negating the expression 5 == 7

Answer 2

5!==7

Question 3

What is the sign for “and”?

What does the sign twice mean?

Answer 3

&
`&& version of AND only evaluates the first member of a vector

TRUE & c(TRUE, FALSE, FALSE)
[1] TRUE FALSE FALSE

TRUE && c(TRUE, FALSE, FALSE)
[1] TRUE

Question 4

sign ad double sign for “or”

Answer 4

The | version of OR evaluates OR across an entire vector, while the || version of OR only evaluates the first member of a vector.

Question 5

Order of operation for and/or

Answer 5

All AND operators are evaluated before OR operators

Question 6

test if arguments are identical?

Answer 6

identical(arg1,arg2)

Question 7

find the indices of ints(a vector) that are greater than 7

Answer 7

which(ints>7)

Question 8

Use a function to see if any of the elements of ints(the vecotr) are less than zero

Answer 8

any(ints<0)

Question 9

Aufbau einer Funktion

Answer 9

https://www.google.com/search?q=function+in+r&rlz=1C1CHBF_deDE908DE908&sxsrf=ALeKk007K5cpEoqcvFGaUNypFk8Y97Sm-w:1594731827554&source=lnms&tbm=isch&sa=X&ved=2ahUKEwi_nN-A58zqAhVzwQIHHZxdAMkQ_AUoAnoECAwQBA&biw=1536&bih=722#imgrc=SWdt5wrRWb927M

Question 10

can you pass functions as arguments?

Answer 10

Yes

Question 11

using evaluate() along with an anonymous function to return the first element of the vector c(8, 4, 0). Your anonymous function should only take one argument which should be a variable x.

Answer 11

evaluate(function(x) {x[1]}, c(8,4,0))

This way you can pass a function as an argument without first defining the passed function. Functions that are not named are appropriately known as anonymous functions.

Question 12

What does … means in a function

Answer 12

infinte amount of arguments is allowed.

Question 13

What does paste() do?

Answer 13

Concatenates charackter strings like paste(“Programming”, “is”, “fun!”) to “Programming is fun!”

Question 14

structure of a simple if statement

Answer 14

if (test_expression) {
statement
}

like in…

x 0){
print(“Positive number”)
}

If the test_expression is TRUE, the statement gets executed. But if it’s FALSE, nothing happens.

Question 15

structure of a simple if else statement

Answer 15

if (test_expression) {
statement1
} else {
statement2
}

x  0){
print("Non-negative number")
} else {
print("Negative number")
}

Question 16

Note structure of if else if else with 4 layers

Answer 16

if ( test_expression1) {
statement1
} else if ( test_expression2) {
statement2
} else if ( test_expression3) {
statement3
} else {
statement4
}

Question 17

Structure of a for loop

Answer 17

for (val in sequence)
{
statement
}

Here, sequence is a vector and val takes on each of its value during the loop. In each iteration, statement is evaluated.

Question 18

Structure of a while loop

Answer 18

while (test_expression)
{
statement
}

i

Question 19

Give an example for a break statement. You create a variable sequence from 1 to 5, iterate a for loop over it and want to break if you get to 3. You want to print the result

Same example, but you want to skip 3 so that you print 
1
2
4
5

Answer 19

x