123 lines
2.4 KiB
Markdown
123 lines
2.4 KiB
Markdown
# Slices vs Arrays Quiz
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## Why you want to use a slice instead of an array?
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1. I like arrays more
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2. I want to create a dynamic collection, so I need an array
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3. A slice's length is dynamic, so I can create dynamic collections *CORRECT*
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## Where does the length of a slice belong to?
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1. Compile-Time
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2. Runtime *CORRECT*
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3. Walk-Time
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4. Sleep-Time
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> **2:** A slice's length is not a part of its type. So its length can change at runtime.
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## Which function call below is correct?
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```go
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// Let's say there's a function like this.
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func sort(nums []int) {
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// ...
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}
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```
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1. sort([...]int{3, 1, 6})
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2. sort([]int32{3, 1, 6})
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3. sort([]int{3, 1, 6}) *CORRECT*
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> **1:** You can't call the sort function using an array. It expects an int slice.
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>
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> **2:** You can't call the sort function using an int32 slice. It expects an int slice.
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>
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> **3:** That's right! You can pass an int slice to the sort function.
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## What is the zero value of this slice?
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```go
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var tasks []string
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```
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1. 0
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2. 1
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3. nil *CORRECT*
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4. unknown
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> **3:** This is a nil slice. Unlike an array, a slice's zero value is nil.
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## What does this code print?
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```go
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var tasks []string
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fmt.Println(len(tasks))
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```
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1. 0 *CORRECT*
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2. 1
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3. nil
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4. It doesn't work.
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> **1:** Yes, you can use the len function on a nil slice. It returns 0 because the slice doesn't contain any elements yet.
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## What does this code print?
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```go
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var tasks []string
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fmt.Println(tasks[0])
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```
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1. 0
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2. 1
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3. nil
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4. It doesn't work. *CORRECT*
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> **4:** You can't get an element that does not exist. A nil slice does not contain any elements.
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## Which declaration below is a correct slice declaration?
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1. [...]int{}
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2. [2]string{"hello", "world"}
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3. []string{"hello", "world"} *CORRECT*
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4. string[2]{"hello", world"}
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## This code doesn't work, why?
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```go
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colors := []string{"red", "blue", "green"}
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tones := []string{"dark", "light"}
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if colors == tones {
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// ...
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}
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```
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1. The slices have different lengths
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2. If statement doesn't contain any statements
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3. Slices cannot be compared *CORRECT*
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> **3:** That's right! A slice value can only be compared to a nil value.
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## What is the length of this slice?
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```go
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[]uint64{}
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```
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1. 64
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2. 1
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3. 0 *CORRECT*
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4. Error
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> **3:** That's right. This is an empty slice, it doesn't contain any elements.
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## What is the length of this slice?
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```go
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[]string{"i'm", "going", "to", "stay", "\"here\""}
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```
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1. 0
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2. 1
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3. 2
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4. 3
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5. 4
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6. 5 *CORRECT* |