Apple Development Little Kee (i): Comparative usage of nsstring

Transferred from: http://blog.sina.com.cn/s/blog_897dd7be0100teh6.html

For a few months, many of the methods of thinking can follow certain rules. NSString Compare strings, I introduce some common methods:

NSString *value = @ "1234567890";

Methods of comparison:

[Value Compare:(NSString *)];

[Value Compare:(NSString *) Options:(nsstringcompareoptions)];

[Value Compare:(NSString *) Options:(nsstringcompareoptions) range:(nsrange)];

Parameters passed in:

Compare: (NSString *)

Pass in a string that needs to be compared.

For example [value compare:@ "1234567890"], return nsorderedsame.

Options: (nsstringcompareoptions)

The value passed into the Nsstringcompareoptions enumeration

enum {

Nscaseinsensitivesearch = 1,// case insensitive comparison

Nsliteralsearch = 2,//Case-sensitive comparison

Nsbackwardssearch = 4,//Start Search from the end of the string

Nsanchoredsearch = 8,//search for a restricted range of strings

Nsnumbericsearch =//According to the numbers in the string, the order is calculated. such as Foo2.txt < Foo7.txt < Foo25.txt

The following definitions are higher than Mac OS 10.5 or more than iphone 2.0 is available

,

Nsdiacriticinsensitivesearch = +,//Ignore "-" symbol comparison

Nswidthinsensitivesearch = up,//Ignore length of string, compare results

Nsforcedorderingsearch =//ignores the option of case-insensitive comparisons and forces the return of nsorderedascending or nsordereddescending

The following definitions are more available than iphone 3.2

,

Nsregularexpressionsearch = 1024x768//can only be applied to rangeofstring: ..., stringbyreplacingoccurrencesofstring: ... and replaceoccurrencesofstring: ... Method. Using a generic compatible comparison method, if you set this, you can remove Nscaseinsensitivesearch and Nsanchoredsearch

}

Range: (Nsrange)

Comparing the range of strings

Structure variables:

Location: The starting position of the string to be compared (starting at 0)

Length: string lengths to compare

return value:

typedef enum _nscomparisonresult {
nsorderedascending = - 1 ,    // < ascending
nsorderedsame, // = equals
nsordereddescending // > Descending
} Nscomparisonresult;