# If else sequences Exercises

**R-exercises**, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here)

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Answers to the exercises are available here.

**Exercise 1**

What is the output of:

`ifelse(sqrt(9)<2,sqrt(9),0)`

**Exercise 2**

What is the output of:

`ifelse(sqrt(100)>9,sqrt(100),0)`

**Exercise 3**

What is the output `y`

of:

`x=12`

`if(is.numeric(x)) y=x*2`

**Exercise 4**

What is the output `x,y`

of:

`z=-1`

`if(z<0){x=abs(z);y=z*3}`

**Exercise 5**

What is the output `y`

of:

`z=6`

`if(z<0) y=z*3 else y=z*5`

**Exercise 6**

What is the output `z`

of:

`x=15`

`y=3`

```
if(is.numeric(x))
if(is.numeric(y) & y!=0)
z=x/y
```

**Exercise 7**

What is the output of:

`x=letters[20]`

```
if (is.numeric(x)) print('is numeric') else
if(is.character(x)) print('is character')
```

**Exercise 8**

What is the output of:

```
x=90
ifelse(x<100,ifelse(x/2==trunc(x/2),x/2,0),
ifelse(x/100==trunc(x/100),x/100,-1))
x=120
ifelse(x<100,ifelse(x/2==trunc(x/2),x/2,0),
ifelse(x/100==trunc(x/100),x/100,-1))
x=200
ifelse(x<100,ifelse(x/2==trunc(x/2),x/2,0),
ifelse(x/100==trunc(x/100),x/100,-1))
```

**Exercise 9**

What is the output `n`

of:

```
z='i'
if (z %in% letters)
if (z=='a') n=1 else
if (z=='e') n=2 else
if (z=='i') n=3 else
if (z=='o') n=4 else n=5
```

**Exercise 10**

What is the output `n`

of:

```
z='u'
if (z %in% letters)
if (z=='a') n=1 else
if (z=='e') n=2 else
if (z=='i') n=3 else
if (z=='o') n=4 else n=5
```

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