In addition to containing the value of a piece of text, strings also contain information about themselves. It can be useful to know these properties when working with strings. There are several built-in .NET methods that we can use to get more information about strings.
Length
Since strings are composed of a set of characters, we can find out how many characters exist in a string with the .Length
method. A common example is if we’re building a form and need to make sure a user submission doesn’t exceed a certain character length.
string userTweet = Console.ReadLine(); userTweet.Length; // returns the length of the tweet
We append the .Length
property to a string that we have, such as a user’s tweet.
IndexOf
We can also find the position of a specific character or substring using .IndexOf()
. This method is useful for searching to see if something exists in a string.
If it does exist within a string, the method will return the position of the search term in the larger string. Each character in a string has a unique position, like an address. Positions starts at 0 and increment by 1.
string word = "radio"; word.IndexOf("a"); // returns 1
Since positioning starts at 0, the second thing in the string will return a 1. If it doesn’t exist in the string the method will return a -1. If we pass it an empty string, it will return 0. If it occurs more than once, it will return the first instance.
Instructions
You’ve been asked to build a program that verifies some information about a piece of data.
First, check the length of password
and save the result to the variable passwordLength
.
Next, let’s see if this password contains any special characters, like an exclamation point (!). Save the result to the variable passwordCheck
. Run the program to see the results printed to the console.