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iOS Swift 2.0 Collections and Control Flow Control Flow With Conditional Statements Working with Logical Operators

Posted by guipriaulx
guipriaulx
551 Points

How is this incorrect?

Question: To start us off, I've written a for loop to iterate over the desired range of values and named the local constant n. Your job is to write an if statement inside the for loop to carry out the desired checks.

If the number is indeed both an odd number and a multiple of 7, append the value to the results array provided.

Hint: To check for an odd number you can either use the remainder operator and 3, or use the not operator to check for "not even"

Preview Output: swift_lint.swift:7:21: error: binary operator '&&' cannot be applied to operands of type 'Bool' and 'Int' if (n % 2 != 0) && (n % 7) {

What is the expected solution?

logicalOperators.swift 
var results: [Int] = []

for n in 1...100 {
    // Enter your code below
    if (n % 7 == 0) && (n % 2 != 0) {
        results += [n]
    }

    // End code
}
guipriaulx
guipriaulx
551 Points

...turns out it accepts it if I use '.append(n)'.

This seems ironic given that earlier in the series, the presenter was all 'Don't worry about remembering the method names, as we will cover this later in more detail...'. I would expect the non-method solution to be preferred since methods have not formally been covered yet, and the web test environment here doesn't offer intellisense.

3 Answers

Steven Deutsch
Steven Deutsch
21,046 Points
Steven Deutsch
Steven Deutsch
21,046 Points

Hey G P,

I think that this challenge wants you to use the append() method to add items to the array instead of using the compound assignment operator as you are now.

var results: [Int] = []

for n in 1...10 {
    // Enter your code below
    if (n % 7 == 0) && (n % 2 != 0) {
        results.append(n)
    }

    // End code
}

Good Luck!

guipriaulx
guipriaulx
551 Points
guipriaulx
guipriaulx
551 Points

As much as I appreciate your reply, I have already stated that this works! Do you have any supporting evidence to suggest why this is the case? The structure of the course lends itself to using the compound assignment instead, and furthermore, the compile issue output doesn't even reflect the code I had written. There is obviously a bug or greater issue here.

As someone with a computer science background and degree, I have found the technical inaccuracies in the course material to be pretty bad at times, but this is really poor form.

Steven Deutsch
Steven Deutsch
21,046 Points
Steven Deutsch
Steven Deutsch
21,046 Points

It's valid code its just not what the question is asking for in the directions. It's asking you to append, not add the value using compound assignment. Therefore, to successfully answer this question you need to use the method they require.

guipriaulx
guipriaulx
551 Points
guipriaulx
guipriaulx
551 Points

I can appreciate that. However, at this point in the course, the presenter has asserted that 'I will not ask for the use of a method without writing how to use the method into the question', and both operations achieve the same means. This also avoids the obvious bug in the 'compiler', if you would even call it that...