Use of objective-C string class nsstring

During the development process, we will encounter a lot of string operations. It is a common data type, and the usage of it is summarized below:

// 1. Create a constant string.
Nsstring * astring = @ "this is a string! ";

// 2. Create an empty string and assign a value.

Nsstring * astring = [[nsstring alloc] init];
Astring = @ "this is a string! ";
Nslog (@ "astring: % @", astring );
[Astring release];

// 3. In the preceding method, the speed is improved by using the initwithstring method.

Nsstring * astring = [[nsstring alloc] initwithstring: @ "this is a string! "];
Nslog (@ "astring: % @", astring );
[Astring release];

// 4. Use Standard C to create a string: initwithcstring Method

Char * cstring = "this is a string! ";
Nsstring * astring = [[nsstring alloc] initwithcstring: cstring];
Nslog (@ "astring: % @", astring );
[Astring release];

// 5. Create a formatted string: A placeholder (consisting of one % and one character)

Int I = 1;
Int J = 2;
Nsstring * astring = [[nsstring alloc] initwithstring: [nsstring stringwithformat: @ "% d. This is % I string! ", I, j];
Nslog (@ "astring: % @", astring );
[Astring release];

// 6. Create a temporary string

Nsstring * astring;
Astring = [nsstring stringwithcstring: "This is a temporary string"];
Nslog (@ "astring: % @", astring );

Nsstring * Path = @ "astring. Text ";
Nsstring * astring = [[nsstring alloc] initwithcontentsoffile: path];
Nslog (@ "astring: % @", astring );
[Astring release];

Nsstring * astring = [[nsstring alloc] initwithstring: @ "this is a string! "];
Nslog (@ "astring: % @", astring );
Nsstring * Path = @ "astring. Text "; 
[Astring writetofile: path atomically: Yes];
[Astring release]; 

// Compare the strcmp function with C

Char string1 [] = "string! ";
Char string2 [] = "string! ";
If (strcmp (string1, string2) = 0)
{
Nslog (@ "1 ");
}

// Isequaltostring Method 
Nsstring * astring01 = @ "this is a string! ";
Nsstring * astring02 = @ "this is a string! ";
Bool result = [astring01 isw.tostring: astring02];
Nslog (@ "Result: % d", result );

// Compare method (three values returned by comparer) 
Nsstring * astring01 = @ "this is a string! ";
Nsstring * astring02 = @ "this is a string! "; 
Bool result = [astring01 compare: astring02] = nsorderedsame; 
Nslog (@ "Result: % d", result ); 
// Determine whether the content of nsorderedsame is the same

Nsstring * astring01 = @ "this is a string! ";
Nsstring * astring02 = @ "this is a string! ";
Bool result = [astring01 compare: astring02] = nsorderedascending; 
Nslog (@ "Result: % d", result );
// Nsorderedascending determines the size of the two objects (which is compared alphabetically. astring02 is true if it is greater than astring01)

Nsstring * astring01 = @ "this is a string! ";
Nsstring * astring02 = @ "this is a string! ";
Bool result = [astring01 compare: astring02] = nsordereddescending; 
Nslog (@ "Result: % d", result ); 
// Nsordereddescending determines the size of the two object values (which are compared alphabetically. astring02 is true if it is smaller than astring01)

// Do not consider comparing strings with uppercase and lowercase letters 1
Nsstring * astring01 = @ "this is a string! ";
Nsstring * astring02 = @ "this is a string! ";
Bool result = [astring01 caseinsensitivecompare: astring02] = nsorderedsame; 
Nslog (@ "Result: % d", result ); 
// Nsordereddescending determines the size of the two object values (which are compared alphabetically. astring02 is true if it is smaller than astring01)

// How to judge whether the string is null

Nsstring * urlstring = [urlinput stringvalue];

 
If (! Urlstring ){ 
 
 
Nslog (@ "no input .");

 
} Else { 
 
If ([urlstring length] = 0 ){

 
Nslog (@ "no input .");

 
} Else {

 
}

 
} 
}