The NSString of Oc--foundation

Tip: Ns:nextstep cg:coregraphics

NSString: Immutable string nsmutablestring: mutable string

URL local file header: file://URL Network File header:/http

int main (int argc, const char * argv[]) {

int age = 10;

1. Creation of strings

NSString *s1 = @ "as God name";

NSString *s2 = [[NSString alloc] initwithstring:@ "Welcome to learn OC"]; Not used

NSString *S3 = [[NSString alloc] initwithformat:@ "Welcome to learn oc, age =%d", age]; Not used

NSString *S4 = [NSString stringwithformat:@ ' Welcome to learn oc, age =%d ', age];

C String---OC string

NSString *S5 = [[NSString alloc] initwithformat:@ "Welcome to learn OC"];

OC string---C string

const char *S5 = [S4 utf8string];

Reading a string from a file

NSString *S6 = [NSString stringwithcontentsoffile:@ "/users/apple/desktop/one.txt" encoding:nsutf8stringencoding Error:nil];

Read the URL string

Nsurl *url = [[Nsurl alloc] initwithstring:@ "File:///Users/apple/Desktop/one.txt"]; Creating a URL Path

Nsurl *URL2 = [Nsurl fileurlwithpath:@ "/users/apple/desktop/one.txt"]; Creating a URL Path

Reading a string from the URL path

NSString *S7 = [[NSString alloc] initwithcontentsofurl:url2 encoding:nsutf8stringencoding Error:nil];

NSLog (@ "%@", S7);

Writing a string to a file

NSString *S8 = @ "Welcome to learn OC";

Nsurl *URL3 = [[Nsurl alloc] initwithstring:@ "File:///Users/apple/Desktop/three.txt"];

[S8 writetofile:url3 atomically:yes encoding:nsutf8stringencoding Error:nil];

Nsmutablestring

nsmutablestring *S10 = [nsmutablestring stringwithformat:@ "Welcome to learn OC"];

[S10 appendstring:@ "Welcome to learn iOS development"]; Stitching the contents to the back of the S1

NSString *S11 = [NSString stringwithformat:@ "Welcome to my Blog"];

NSString *s12 = [S2 stringbyappendstring:@ "and other ..."]; Add a string after S11

Get string length
Nsuinteger length = Str.length
Gets the character of a position in a string
Unichar c = [str characteratindex:1];

return 0;

}

The NSString of Oc--foundation