Use the built-in “+” or “-” functions, or their shorthand “1+” or “1-“, if you just want to use the result, without modifying the original number (the argument). If you do want to modify the original place (containing a number), then use the built-in “incf” or “decf” functions. Using the addition operator: (setf num 41) … Read more
Here is an easier (and more Swifty) approach. for i in (0 ..< 5).reversed() { print(i) // 4,3,2,1,0 } let array = [“a”, “b”, “c”, “d”, “e”] for element in array.reversed() { print(element) // e,d,c,b,a } array.reversed().forEach { print($0) } // e,d,c,b,a print(Array(array.reversed())) // e,d,c,b,a
In C, –x is a value, not an lvalue. Its effect is to decrement x, and evaluate to the newly assigned value of x. Since –x is not an lvalue, it cannot be decremented. In C++, –x is an lvalue, not an rvalue. Its effect is to decrement x, and evaluate to x as an … Read more
Add another condition to update only if the field is greater 0 UPDATE your_table SET field = field – 1 WHERE id = $number AND field > 0
a = ” “.join(str(i) for i in range(10, 0, -1)) print (a)
A full explanation here from Chris Lattner, Swift’s creator. I’ll summarize the points: It’s another function you have to learn while learning Swift Not much shorter than x += 1 Swift is not C. Shouldn’t carry them over just to please C programmers Its main use is in C-style for loop: for i = 0; … Read more
! inverts a value, and gives you the opposite boolean: !true == false !false == true !1 == false !0 == true –[value] subtracts one (1) from a number, and then returns that number to be worked with: var a = 1, b = 2; –a == 0 –b == 1 So, !–pending subtracts one … Read more
++ is not an operator. It is two + operators. The + operator is the identity operator, which does nothing. (Clarification: the + and – unary operators only work on numbers, but I presume that you wouldn’t expect a hypothetical ++ operator to work on strings.) ++count Parses as +(+count) Which translates to count You … Read more