Exercise

# Counting matches

Another `stringr`

function that takes a vector of strings and a pattern is `str_count()`

. `str_count()`

answers the question "How many times does the pattern occur in each string?". It always returns an integer vector of the same length as that of the input vector.

If you count the occurrences of `"pepper"`

in your `pizzas`

, you'll find no occurrences in the first, and one each in the second and third,

```
pizzas <- c("cheese", "pepperoni",
"sausage and green peppers")
str_count(pizzas, pattern = fixed("pepper"))
```

Perhaps a little more interesting is to count how many `"e"`

s occur in each order

```
str_count(pizzas, pattern = fixed("e"))
```

You'll use `str_count()`

to find some names with lots of repeated letters.

Instructions

**100 XP**

- Count the number of
`"a"`

in each`girl_names`

, store in`number_as`

. - Count the number of
`"A"`

in each`girl_names`

, store in`number_As`

. - Create histograms, use the
`hist()`

function, of`number_as`

and`number_As`

.*Why is*`number_As`

only zero or one? - Add together
`number_as`

and`number_As`

to get`total_as`

. - Subset
`girl_names`

to only those names where`total_as > 4`

.