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Adding/Updating Array Elements in .NET Encode barcode pdf417 in .NET Adding/Updating Array Elements

Adding/Updating Array Elements generate, create barcode pdf417 none on .net projects Developing with Visual Studio .NET >>> a[2] = "three";. Using the in dex, you can also update elements of the array. The next example updates the third element (index 2) and prints the contents of the new array..

"three". >>> a [1, 2, "three"] You can add more elements, by addressing an index that didn"t exist before. >>> a[3] = "four";. "four". >>> a [1, 2, "three", "four"]. [ 45 ]. Primitive Data Types, Arrays, Loops, and Conditions If you add a new element, but leave a gap in the array, those elements in between are all assigned the undefined value. Check out this example:. >>> pdf417 for .NET var a = [1,2,3]; >>> a[6] = "new";. "new". >>> a [1, 2, 3, un defined, undefined, undefined, "new"]. Deleting Elements In order to delete an element, you can use the delete operator. It doesn"t actually remove the element, but sets its value to undefined. After the deletion, the length of the array does not change.

. >>> Visual Studio .NET pdf417 var a = [1, 2, 3]; >>> delete a[1];. true >>> a [1, undefined, 3]. Arrays of arrays An array can contain any type of values, including other arrays. >>> var a = [1, "two", false, null, undefined]; >>> a [1, "two", f alse, null, undefined]. >>> a[5] = [1,2,3]. [1, 2, 3]. >>> a [1, "two", f alse, null, undefined, [1, 2, 3]]. [ 46 ]. 2 . Let"s see an example where you have an array of two elements, each of them being an array. >>> var a = [[1,2,3],[4,5,6]]; >>> a [[1, 2, 3], [4, 5, 6]] The first element of the array is a[0] and it is an array itself. >>> a[0]. [1, 2, 3] To Visual Studio .NET barcode pdf417 access an element in the nested array, you refer to the element index in another set of square brackets..

>>> a[0][0]. >>> a[1][2]. 6 Note also that you can use the array notation to access individual characters inside a string. >>> var s = "one"; >>> s[0]. >>> s[1]. >>> s[2]. "e" There ar e more ways to have fun with arrays (and we"ll get to that in 4), but let"s stop here for now, remembering that: An array is a data store An array contains indexed elements Indexes start from zero and increment by one for each element in the array To access array elements we use the index in square brackets An array can contain any type of data, including other arrays. [ 47 ]. Primitive Data Types, Arrays, Loops, and Conditions Conditions and Loops if con ditions, switch statements,. Conditions p PDF417 for .NET rovide a simple but powerful way to control the flow of execution through a piece of code. Loops allow you to perform repeating operations with less code.

Let"s take a look at:. while, do-while, for, and for-in loops. Code Blocks Let"s start by clarifying what a block of code is, as blocks are used extensively when constructing conditions and loops. A block of code consists of zero or more expressions enclosed in curly brackets..

{ var a = 1; var b = 3; }. You can nest blocks within each other indefinitely:. { var var va barcode pdf417 for .NET r { c { } } } a = 1; b = 3; c, d; = a + b; d = a - b;. [ 48 ]. 2 . Best Practic e Tips Use end-of-line semicolons. Although the semicolon is optional when you have one expression per line, it"s good to develop the habit of using them. For best readability, the individual expressions inside a block should be placed one per line and separated by semi-colons.

Indent any code placed within curly brackets. Some people use one tab indentation, some use four spaces, and some use two spaces. It really doesn"t matter, as long as you"re consistent.

In the example above the outer block is indented with two spaces, the code in the first nested block is indented with four spaces and the innermost block is indented with six spaces. Use curly brackets. When a block consists of only one expression, the curly brackets are optional, but for readability and maintainability, you should get into the habit of always using them, even when they"re optional.

. Ready to jum .NET barcode pdf417 p into loops and ifs Note that the examples in the following sections require you to switch to the multi-line Firebug console..

if Conditions Here"s a sim PDF417 for .NET ple example of an if condition:. var result = ""; if (a > 2) { result = "a is greater than 2"; }. The parts of .net vs 2010 pdf417 2d barcode the if condition are: The if statement A condition in parentheses "is a greater than 2 " Code block to be executed if the condition is satisfied. The conditio n (the part in parentheses) always returns a boolean value and may contain: A logical operation: !, && or . A compariso visual .net PDF417 n, such as ===, !=, >, and so on Any value or variable that can be converted to a boolean A combination of the above. [ 49 ].
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