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C# – Find a character in a string

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There are three methods you can use to find a character in a string: I’ll show examples below. Using string.IndexOf() to find a character string.IndexOf() returns the index of the first occurrence of a character in a string. It searches the string from left to right, starting at the beginning. If it doesn’t find the … Read more

C# – Remove spaces from a string

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The simplest way to remove spaces from a string is by using string.Replace(). Here’s an example: This outputs the following. Notice the spaces are removed. string.Replace() is good for removing all occurrences of a specific character (” ” in this case). When you want to remove all whitespace characters (spaces, tabs, newlines, etc..), there are … Read more

C# – Remove first or last character from a string

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Use string.Remove() to remove character(s) from a string based on their index, such as the first or last character. This method has two parameters: string.Remove() returns a new string with the characters removed. I’ll show examples below. Remove the first character from a string To remove the first character, use string.Remove(startIndex: 0, count: 1), like … Read more

C# – How to convert char to int

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Converting a char to an int means getting the numeric value that the char represents (i.e. ‘1’ to 1). This is not the same as casting the char to an int, which gives you the char’s underlying value (i.e. ‘1’ is 49). There are three ways to convert a char to an int: I’ll show … Read more

C# – Use yield return to minimize memory usage

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Let’s say you want to search for specific characters in a large text file and return a list of context objects to the calling code for further processing (such as showing the results in the UI). One way to do that is to build the entire list at once and return it. If you don’t … Read more

C# – Save a list of strings to a file

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The simplest way to save a list of strings to a file is to use File.WriteAllLines(). This creates (or overwrites) the file and writes each string on a new line. The resulting file looks like this: Note: Showing non-printable newline characters \r\n for clarity. Specifying the separator character What if you want to separate each … Read more

C# – Remove non-alphanumeric characters from a string

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The simplest way to remove non-alphanumeric characters from a string is to use regex: Note: Don’t pass in a null, otherwise you’ll get an exception. Regex is the simplest options for removing characters by “category” (as opposed to removing arbitrary lists of characters or removing characters by position). The downside is that regex is the … Read more

C# – Remove a list of characters from a string

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When you want to remove a list of characters from a string, loop through the list and use string.Replace(): Note that string.Replace() returns a new string (because strings are immutable). Running this outputs the following: This is the fastest approach (in .NET 6+). Linq approach: Where() + ToArray() + new string() Another option for removing … Read more

C# – Hex string to byte array

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This article shows code for converting a hex string to a byte array, unit tests, and a speed comparison. First, this diagram shows the algorithm for converting a hex string to a byte array. To convert a hex string to a byte array, you need to loop through the hex string and convert two characters … Read more