ios--String Common Properties

1. String concatenation

nsstring* string; Result string

nsstring* string1 = @ "WOSHIZTQ"; Existing string, string1 and string2 need to be connected together

NSString *string2= @ "13456";

Method 1.

string = [NSString stringwithformat:@ "%@%@", string1, string2];

//Method 2

string = [string1 stringbyappendingstring:string2];

Method 3.

string = [string stringbyappendingformat:@ "%@%@", string1, string2];

/*--------Delete the character in the existing string according to the given range and length------*/

[String1 deletecharactersinrange:nsmakerange (0, 5)];

/*--------Insert the given string in the specified position after the existing string------*/

[String1 insertstring:@] hi! [atindex:0];

2. String interception

NSString *string2 = [string1 substringtoindex:3]; Intercepts from the beginning of a string to the specified position, but not the character at that position (that is, the first n characters are truncated)

NSString *string2 = [string1 substringfromindex:3]; Starts at the specified position (including the character at the specified position) and includes all subsequent characters (intercepts all characters of the first n)

NSString *string2 = [string1 substringwithrange:nsmakerange (0, 4)]; Arbitrarily intercept substrings from a string in the given position, length

3. String comparison and judgment

BOOL result = [Astring01 compare:astring02
Options:nscaseinsensitivesearch |       Nsnumericsearch] = = Nsorderedsame; Do not consider case comparison string 2

Newkeys = [string Sortedarrayusingcomparator:result]; String size sorting

Nsarray *array1=[str1 componentsseparatedbystring:@ "."];/ /String Segmentation

/*-------------Determine if the string also contains other strings (prefixes, suffixes)-------------*/
NSString *string1 = @ "NSStringInformation.txt";
[String1 hasprefix:@ "nsstring"] = = 1? NSLog (@ "YES"): NSLog (@ "NO");
[String1 hassuffix:@ ". txt"] = = 1? NSLog (@ "YES"): NSLog (@ "NO");

4. String file operation

Read File contents

NSString *[email protected] "/users/kenshincui/desktop/test.txt"; NSString *str1=[nsstring Stringwithcontentsoffile:path encoding:nsutf8stringencoding Error:nil];

Since we have Chinese in the test.txt, we can get an error using the following code, which shows the procedure

Nserror *error; NSString *str2=[nsstring Stringwithcontentsoffile:path encoding:kcfstringencodinggb_18030_2000 error:&error];/ /Note that the error variable in this sentence is **error, that is, the pointer is the pointer's address, because error is a pointer here is the address of error &error,

if (Error) {NSLog (@ "read error, the error is%@", error);}

else{NSLog (@ "read Success,the file content is%@", str2);}

One way to read the contents of a file is to use the URL, which can read the network file in addition to the local file

Nsurl *url=[nsurl urlwithstring:@ "File:///Users/kenshincui/Desktop/test.txt"];

Nsurl *url=[nsurl urlwithstring:@ "http://www.apple.com"];

NSString *str3=[nsstring stringwithcontentsofurl:url encoding:nsutf8stringencoding Error:nil];

Here is the file write

NSString *[email protected] "/users/kenshincui/desktop/test2.txt";

Nserror *error1; NSString *[email protected] Hello world, Hello! ";

[Str11 writetofile:path1 Atomically:yes encoding:nsutf8stringencoding error:&error1];//automically represents a write-once, If it goes wrong in the middle, it's not written at all.

if (Error1) {NSLog (@ "Write fail,the error is%@", [Error1 localizeddescription]);//Call localizeddescription to print only critical error messages}

else{NSLog (@ "Write success!");}

5. Variable string

/*--------swop existing empty characters into other strings------*/  
      
    nsmutablestring *string1 = [[Nsmutablestring alloc] initwithstring:@ "This is a nsmutablestring"];  
    [string1 setstring:@ "Hello Word! "];  

/*--------The original characters replaced by the given range, and the string------*/

-setstring:
nsmutablestring *string1 = [[Nsmutablestring alloc] initwithstring:@ "This is a nsmutablestring"];
[String1 replacecharactersinrange:nsmakerange (0, 4) withstring:@ "that"];
NSLog (@ "string1:%@", String1);

　　

ios--string Common Properties