一、NSString字符串连接
NSString* string; // 结果字符串NSString* string1, string2; //已存在的字符串
1. string = [NSString initWithFormat:@"%@,%@", string1, string2 ];2. string = [string1 stringByAppendingString:string2];</p>3 . string = [string stringByAppendingFormat:@"%@,%@",string1, string2];4 . string = [string stringByAppendingFormat:@"%@%@%@%@%@%@",string1, string2, string3, string4......];
可以拼接很多，%@中间加逗号字符串里也带逗号
二、NNString用法
----- 创建字符串的方法-----
//1、创建常量字符串
NSString *astring = @"This is a String!";
//2、先创建一个空的字符串，然后赋值；
// alloc和init组合则适合在函数之间传递参数，用完之后需要手工release
NSString *astring = [[NSString alloc] init]; astring = @"This is a String!"; NSLog(@"astring:%@",astring); [astring release];
//3、在以上方法中，提升速度:initWithString方法
NSString *astring = [[NSString alloc] initWithString:@"This is a String!"]; NSLog(@"astring:%@",astring); [astring release]; //4、创建临时字符串
NSString *astring; astring = [NSString stringWithCString:"This is a temporary string"]; NSLog(@"astring:%@",astring);
// OR
NSString * scriptString = [NSString stringWithString:@" tell application \"Mail\"\r"];
//5、创建格式化字符串:占位符（由一个%加一个字符组成）
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];
-----从文件读取字符串-----
NSString *path = @"astring.text"; NSString *astring = [[NSString alloc] initWithContentsOfFile:path]; NSLog(@"astring:%@",astring); [astring release];-----写字符串到文件----
NSString *astring = [[NSString alloc] initWithString:@"This is a String!"]; NSLog(@"astring:%@",astring); NSString *path = @"astring.text"; [astring writeToFile: path atomically: YES]; [astring release]; -----比较两个字符串-----//1、用C比较:strcmp函数 char string1[] = "string!"; char string2[] = "string!"; if(strcmp(string1, string2) = = 0) { NSLog(@"1"); } //2、isEqualToString方法 NSString *astring01 = @"This is a String!"; NSString *astring02 = @"This is a String!"; BOOL result = [astring01 isEqualToString:astring02]; NSLog(@"result:%d",result);//3、compare方法(comparer返回的三种值：NSOrderedSame，NSOrderedAscending，NSOrderedDescending) NSString *astring01 = @"This is a String!"; NSString *astring02 = @"This is a String!"; BOOL result = [astring01 compare:astring02] = = NSOrderedSame; //NSOrderedSame 判断两者是否相同 NSLog(@"result:%d",result);NSString *astring01 = @"This is a String!";
NSString *astring02 = @"this is a String!"; BOOL result = [astring01 compare:astring02] = = NSOrderedAscending; NSLog(@"result:%d",result); //NSOrderedAscending 判断两对象值的大小(按字母顺序进行比较，astring02大于astring01为真)NSString *astring01 = @"this is a String!";
NSString *astring02 = @"This is a String!"; BOOL result = [astring01 compare:astring02] = = NSOrderedDescending; NSLog(@"result:%d",result); //NSOrderedDescending 判断两对象值的大小(按字母顺序进行比较，astring02小于astring01为真) //4、不考虑大小写比较字符串1 NSString *astring01 = @"this is a String!"; NSString *astring02 = @"This is a String!"; BOOL result = [astring01 caseInsensitiveCompare:astring02] = = NSOrderedSame; NSLog(@"result:%d",result); //NSOrderedDescending判断两对象值的大小(按字母顺序进行比较，astring02小于astring01为真)//5、不考虑大小写比较字符串2 NSString *astring01 = @"this is a String!"; NSString *astring02 = @"This is a String!"; BOOL result = [astring01 compare:astring02 options:NSCaseInsensitiveSearch | NSNumericSearch] = = NSOrderedSame; NSLog(@"result:%d",result); //NSCaseInsensitiveSearch:不区分大小写比较 NSLiteralSearch:进行完全比较，区分大小写 NSNumericSearch:比较字符串的字符个数，而不是字符值。 三、打印日志
NSLog(@"%@ ",order);//打印字典
NSLog(@"%@ ",imageUrlString);