How to check if NSString begins with a certain character

Question

How do you check if an NSString begins with a certain character  the character      The   is an indicator for the type of the cell  so I need the contents of this NSString without the    but need to know if the   exists

User · Answer

As a more general answer  try using the hasPrefix method  For example  the code below checks to see if a string begins with 10  which is the error code used to identify a certain problem   NSString  myString     10 Username taken    if  myString hasPrefix   10              display more elegant error message

User · Answer

You can use   NSString  newString  if     myString characterAtIndex 0  isEqualToString                newString    myString substringFromIndex 1

User · Answer

Use characterAtIndex   If the first character is an asterisk  use substringFromIndex  to get the string sans

User · Answer

Another approach to do it    May it help someone     if    temp substringToIndex 4  isEqualToString   http          starts with http

User · Answer

This might help      http   developer apple com mac library documentation Cocoa Reference Foundation Classes NSString Class Reference NSString html   apple ref occ instm NSString characterAtIndex   Just search for the character at index 0 and compare it against the value you re looking for

User · Answer

NSString  stringWithoutAsterisk NSString  string        NSRange asterisk    string rangeOfString            return asterisk location    0    string substringFromIndex 1    string

User · Answer

NSString  expectedString   nil  if  givenString hasPrefix             expectedString    givenString substringFromIndex 1

User · Answer

hasPrefix works especially well  for example if you were looking for a http url in a NSString  you would use componentsSeparatedByString to create an NSArray and the iterate the array using hasPrefix to find the elements that begin with http      NSArray  allStringsArray        myStringThatHasHttpUrls componentsSeparatedByString        for  id myArrayElement in allStringsArray        NSString  theString    myArrayElement description       if   theString hasPrefix   http              NSLog   The URL  is       myArrayElement description               hasPrefix returns a Boolean value that indicates whether a given string matches the beginning characters of the receiver   -  BOOL hasPrefix  NSString   aString     parameter aString is a string that you are looking for Return Value is YES if aString matches the beginning characters of the receiver  otherwise NO  Returns NO if aString is empty

User · Answer

You can use the -hasPrefix  method of NSString   Objective-C   NSString  output   nil  if  string hasPrefix              output    string substringFromIndex 1       Swift   var output String  if string hasPrefix            output   string substringFromIndex string startIndex advancedBy 1

User · Answer

This nice little bit of code I found by chance  and I have yet to see it suggested on Stack  It only works if the characters you want to remove or alter exist  which is convenient in many scenarios  If the character s does not exist  it won t alter your NSString   NSString    yourString stringByReplacingOccurrencesOfString   YOUR CHARACTERS YOU WANT TO REMOVE  withString   CAN either be EMPTY or WITH TEXT REPLACEMENT      This is how I use it     declare what to look for NSString   suffixTorRemove      amp lt  p amp gt    NSString   prefixToRemove      amp lt p amp gt    NSString   randomCharacter      amp lt  strong amp gt    NSString   moreRandom      amp lt strong amp gt    NSString   makeAndSign      amp amp amp       I AM INSERTING A VALUE FROM A DATABASE AND HAVE ASSIGNED IT TO returnStr returnStr    returnStr stringByReplacingOccurrencesOfString suffixTorRemove withString       returnStr    returnStr stringByReplacingOccurrencesOfString prefixToRemove withString       returnStr    returnStr stringByReplacingOccurrencesOfString randomCharacter withString       returnStr    returnStr stringByReplacingOccurrencesOfString moreRandom withString       returnStr    returnStr stringByReplacingOccurrencesOfString makeAndSign withString    amp        check the output NSLog   returnStr IS NOW       returnStr     This one line is super easy to perform three actions in one    Checks your string for the character s you do not want Can replaces them with whatever you like Does not affect surrounding code

[objective-c] How to check if NSString begins with a certain character

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