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iOS Swift Basics (retired) Control Flow For-In Loop

Brian Uribe
Brian Uribe
3,488 Points
Posted by Brian Uribe
Brian Uribe
3,488 Points

I didn't fully understand the video

I'm confused on this challenge task. I'm not 100% sure what i'm doing. I know I keep asking questions, but someone please help, much appreciated.

for_loops.swift 
for number in 1...10 {
      println("/(number) times 7 is / (number*")

      }

1 Answer

Richard Lu
Richard Lu
20,185 Points
Richard Lu
Richard Lu
20,185 Points

Hey Brian,

Let's take this problem step at a time.

The challenge wants you to print out the multiples of 7. So something like this:

1 * 7
2 * 7 
3 * 7
// and so on

In order to achieve the left operand (1-10), we'll use a for-in loop.

for i in 1...10 {
   // loops from 1 to 10 and stores each iteration onto i. Just what we need!
}

The last step is to actually do the multiplying and printing.

for i in 1...10 { // use the loop from before
   let multiple = i * 7    // multiple now contains a multiple of 7
   println("\(i) * 7 = \(multiple)")   // using "string interpolation", we can encapsulate other objects onto our string.
}

If you have any other questions, feel free to ask! It's a learning environment :)

- Rich

Brian Uribe
Brian Uribe
3,488 Points
Brian Uribe
Brian Uribe
3,488 Points

Hello!

I'm sorry but i'm still struggling to understand. The video that goes along with this was fairly vague, I wasn't sure why they were doing what they were doing. Can you break down the last part? I understand that "i" represent any number from 1-10, and when we say i * 7, we are saying all numbers from 1-10 will be multiplied by 7, but the last part, the ("(i) * 7 = (multiple)". Also, I keep getting this challenge question wrong. Can you give me the answer and give me a break down of why that answer is correct?

Richard Lu
Richard Lu
20,185 Points
Richard Lu
Richard Lu
20,185 Points

Hey Brian,

You're answer is pretty close. Here's the answer: 

for i in 1...10 { // use the loop from before
   let multiple = i * 7    // multiple now contains a multiple of 7
   println("\(i) * 7 = \(multiple)")   // using "string interpolation", we can encapsulate other objects onto our string.
}

To break down the last part (string interpolation), let say we have the strings "hello" and "world". In order to combine the two strings together, you have the following:

let helloString = "hello"
let worldString = "world"

// combining the string

let helloWorldString = helloString + worldString    // helloWorldString holds "helloworld"

There are different ways of accomplishing something when you program. Another way to combine the two strings is a method called string interpolation. Here's an example:

let helloString = "hello"
let worldString = "world"

// combining the string
// the '\()'s act as blank lines (an analogy) and you fill whatever you want in between
let helloWorldString = "\(helloString)\(worldString)"   // there are two blank lines in this example

In the challenge, they want you to have an output of the following format

1 * 7 = 7
2 * 7 = 14
and so on

In order to accomplish that, we'll use "blank lines"/string interpolation \().

println("\(i) * 7 = \(i*7)")

Let me know if there are any additional questions. :)