The difference between OC and Swift four

12. The difference between conditional statements, where only the difference is written here, does not point out the difference in other respects OC is basically consistent with Swift

12.1

For if switch statement body in OC If there is only one line of code, {} can omit

The body of the for if switch statement in Swift must use {}, otherwise there is a syntax error

Differences in 12.2for-in syntax:

Cycle from 1 to 3, including 3, i.e. 3 cycles

For I in 1..3{

}

If you do not need to use a value in the loop condition range, use _ to ignore the loop condition value so that it does not create a local variable in the loop body

For _ in 1..3{

}

The cyclic condition value is constant and cannot be changed in the loop body

For I in 1...3{

i = 10//This code error

}

The difference between OC and Swift four