Course String manipulation in C#

Course String manipulation in C#

String formatting

•  String.Format(formatstring, arguments)
•  Also supported by Console.WriteLine() and others
•  Format string contains groups of the form {index[,alignment][:codes]}

•    Index of first argument after format string is 0
•    Alignment specifies number of characters to use (padded with spaces at left if positive, at right if negative)
•    Codes are interpreted based on the value’s type
•    Alignment and codes can be omitted
•  Relies extensively on objects’ ToString() method

Some formatting codes

•  For numbers n – use comas to separate thousands,e – scientific notation, x and X – hexadecimal, 0indicates padding with 0s, # indicates position of digits (see demo4)
•  For dates and times: d and D – short/long date, t/T – short/long time, mm – a minutes, MM – month asnumber, MMM – month as 3 letter code, MMMM – month name
•  g stands for the generic default format for all types
•  For more details on formatting see http://blog.stevex.net/index.php/string-formattingin- csharp/

String manipulation methods

•  Some methods of the String class
•  Trim() removes whitespaces from both ends of string
•  Split(char[] separators) splits string into an array of substrings separated by the given characters
•  SubString(int index, int length) extracts the substring of given length from the given position
•  IndexOf(string substring, int startIndex) finds first occurrence of given substring after given index
•  LastIndexOf(string substring) finds last indexwhere substring occurs
•  Replace(string oldValue, string newValue)

StringBuilder

•  Strings are immutable objects
•  Whenever a new string created, it uses a new memory location
•  This happens whenever strings are concatenated, trimmed, characters replaced, etc.
•  Inefficient if a large string built by many small changes
•  The StringBuilder class allows more efficient inplace manipulation
•  Appending strings, replacing substrings and characters, removing substrings, etc............

Course String manipulation in C#