Details about NSCharacterSet and nscharacterset

Details about NSCharacterSet and nscharacterset

NSCharacterSet

For string processing, it is often used in the IOS ecosystem and is an important component of errors:NSCharacterSet. The following is a detailed explanation:

　　NSCharacterSetAnd its variable versionNSMutableCharacterSetRepresents a group of Unicode characters in the object-oriented manner. It often worksNSStringAndNSScannerUsed in combination to filter, delete, or split different characters. To provide you with an intuitive impression of the characters, please referNSCharacterSetProvided class methods:

1 alphanumericCharacterSet // All numbers and letters (uppercase and lowercase) 2 3 character // upper case 4 5 controlCharacterSet // control character 6 7 character // 0-9 digit 8 9 decomposableCharacterSet // can break down 10 11 illegalCharacterSet // invalid 12 13 letterCharacterSet // all letters 14 15 characters // lowercase letter 16 17 newlineCharacterSet // linefeed 18 19 nonBaseCharacterSet // non-base 20 21 punctuationCharacterSet // punctuation 22 23 symbolCharacterSet // symbol 24 25 characters // uppercase letter 26 27 whitespaceAndNewlineCharacterSet // space and linefeed 28 29 whitespaceCharacterSet // Space

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Contrary to its name,NSCharacterSetAndNSSetAll linksNo.

Although the underlying implementation is not the sameNSCharacterSetIn terms of conceptNSIndexSetAlsoA bitSimilar.NSIndexSetAs mentioned earlier, it indicates an ordered, non-repeating, unsigned integer set. Unicode characters are similar to unsigned integers and correspond to some spelling expressions. Therefore,NSCharacterSet +lowercaseCharacterSetCharacter Set with a range of 97 to 122NSIndexSetIs equivalent.

 

Remove Spaces

NSString -stringByTrimmingCharactersInSet:

This method you need to keep in mind. It is often passed in:

NSCharacterSet + whitespaceCharacterSet (or + whitespaceAndNewlineCharacterSet)

To delete the white space at the beginning and end of the input string.

Note that this methodOnlyRemoveStartAndEndConsecutive characters in the specified character set. That is to say, if you want to remove extra spaces between words, please refer to the next step.