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I can't figure out why this isn't working. I think I'm not understanding the for. . .in construct.

For example, with the statement:

for month in months {

what is "month" exactly? does it need to be declared as a variable? The explanation in the video wasn't very helpful/precise enough.

months.swift
```let months = [1, 2, 3]
for month in months {
if months[month] == 1 {
println("January")
} else if months[month] == 2 {
println("February")
} else {
println("March")
}
}
```

months is an array of integers 1, 2, and 3.

month is one of those integers. So you don't need to access it like a typical array, since 'month' is standing in for the value of that index.

```let months = [1, 2, 3]

for month in months {
if month == 1 {
println("January")
} else if month == 2 {
println("February")
} else {
println("March")
}
}
```

Thanks! I think I get it now. So to make sure I understand how this works.

• month is a variable that refers to the value of the array at whatever index
• the for. . in loop goes sequentially through the values of the array (e.g., months[0], months[1], months[2]. . .) until it goes through the entire array

Does that also mean month is declared implicitly? In this and the other samples of for. . .in loops, the variable after the "for" is never declared.

When it comes to 'month', when you write "for month in months", you are essentially declaring a new constant named month of type Int.

```let month: Int
```

Now, month can be used to reference any of the Int values within the array. Note that month cannot be assigned to any of the integers in the array, only compared (==).