创建字符串。

NSString *astring = @"This is a String!";
创建空字符串，给予赋值。

NSString *astring = [[NSString alloc] init];

astring = @"This is a String!";

NSLog(@"astring:%@",astring);

string release];
使用变量初始化

NSString *name = @"Ivan!";
NSString *astring = [[NSString stringWithFormat:@”My name is %@!”,name]];
NSLog(@"astring:%@",astring);
判断是否包含某字符串

检查字符串是否以另一个字符串开头

- (BOOL) hasPrefix: (NSString *) aString;
NSString *String1 = @"NSStringInformation.txt";
[String1 hasPrefix:@"NSString"] == 1 ?  NSLog(@"YES") : NSLog(@"NO");
[String1 hasSuffix:@".txt"] == 1 ?  NSLog(@"YES") : NSLog(@"NO");
是否包含其它字符

NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];
Boolean contains = [astring rangeOfString:@”This”].length>0;
从文件读取字符串:

initWithContentsOfFile方法
NSString *path = @"astring.text";
NSString *astring = [[NSString alloc] initWithContentsOfFile:path];
NSLog(@"astring:%@",astring);
[astring release];
写字符串到文件:writeToFile方法

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

isEqualToString方法

NSString *astring01 = @"This is a String!";
NSString *astring02 = @"This is a String!";
BOOL result = [astring01 isEqualToString:astring02];
NSLog(@"result:%d",result);
compare方法(comparer返回的三种值)

NSString *astring01 = @"This is a String!";
NSString *astring02 = @"This is a String!";
BOOL result = [astring01 compare:astring02] = = NSOrderedSame;
NSLog(@"result:%d",result);
NSOrderedSame判断两者内容是否相同

NSString *astring01 = @"This is a String!";
NSString *astring02 = @"this is a String!";
BOOL result = [astring01 compare:astring02] = = NSOrderedAscending;
NSLog(@"result:%d",result);
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);
改变字符串的大小写

NSString *string1 = @"A String";
NSString *string2 = @"String";
NSLog(@"string1:%@",[string1 uppercaseString]);//大写
NSLog(@"string2:%@",[string2 lowercaseString]);//小写
NSLog(@"string2:%@",[string2 capitalizedString]);//首字母大小
在串中搜索子串

NSString *string1 = @"This is a string";
NSString *string2 = @"string";
NSRange range = [string1 rangeOfString:string2];
int location = range.location;
int leight = range.length;
NSString *astring = [[NSString alloc] initWithString:[NSString stringWithFormat:@"Location:%i,Leight:%i",location,leight]];
NSLog(@"astring:%@",astring);
[astring release];
替换字符串

NSString *astring01 = @"hello 中国";
NSString * new = [astring01 stringByReplacingOccurrencesOfString:@”中国” withString:@"北京"];
NSLog(new);
分割字符串成数组

NSString *s = @"a b d e f";
NSArray *arr = [s componentsSeparatedByString:@" "];
NSLog(@"count = %d",[arr count]);
字符串数组拼接成字符串

NSArray *pathArray = [NSArray arrayWithObjects:@"here",
                      @"be", @"dragons", nil];
NSLog(@"%@",[pathArray componentsJoinedByString:@""]);
抽取子串

-substringToIndex: 从字符串的开头一直截取到指定的位置，但不包括该位置的字符

NSString *string1 = @"This is a string";
NSString *string2 = [string1 substringToIndex:3];
NSLog(@"string2:%@",string2);
-substringFromIndex: 以指定位置开始（包括指定位置的字符），并包括之后的全部字符

NSString *string1 = @"This is a string";
NSString *string2 = [string1 substringFromIndex:3];
NSLog(@"string2:%@",string2);
-substringWithRange: //按照所给出的位置，长度，任意地从字符串中截取子串

NSString *string1 = @"This is a string";
NSString *string2 = [string1 substringWithRange:NSMakeRange(0, 4)];
NSLog(@"string2:%@",string2);
二、NSMutableString

给字符串分配容量

//stringWithCapacity:
NSMutableString *String;
String = [NSMutableString stringWithCapacity:40];
在已有字符串后面添加字符

//appendString: and appendFormat:
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
//[String1 appendString:@", I will be adding some character"];
[String1 appendFormat:[NSString stringWithFormat:@", I will be adding some character"]];
NSLog(@"String1:%@",String1);
*/
在已有字符串中按照所给出范围和长度删除字符

//deleteCharactersInRange:
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
[String1 deleteCharactersInRange:NSMakeRange(0, 5)];
NSLog(@"String1:%@",String1);
在已有字符串后面在所指定的位置中插入给出的字符串

//-insertString: atIndex:
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
[String1 insertString:@"Hi! " atIndex:0];
NSLog(@"String1:%@",String1);
将已有的换成其它的字符串

//-setString:
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
[String1 setString:@"Hello Word!"];
NSLog(@"String1:%@",String1);
按照所给出的范围，和字符串替换的原有的字符

//-setString:
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
[String1 replaceCharactersInRange:NSMakeRange(0, 4) withString:@"That"];
NSLog(@"String1:%@",String1);
三、NSArray

创建数组

NSArray *array = [[NSArray alloc] initWithObjects:
                  @"One",@"Two",@"Three",@"Four",nil];
self.dataArray = array;
[array release];
//- (unsigned) Count;数组所包含对象个数；
NSLog(@"self.dataArray cound:%d",[self.dataArray count]);
//获取指定索引处的对象
NSLog(@"self.dataArray cound 2:%@",[self.dataArray objectAtIndex:2]);
从一个数组拷贝数据到另一数组

//arrayWithArray:
//NSArray *array1 = [[NSArray alloc] init];
NSMutableArray *MutableArray = [[NSMutableArray alloc] init];
NSArray *array = [NSArray arrayWithObjects:
                  @"a",@"b",@"c",nil];
NSLog(@"array:%@",array);
MutableArray = [NSMutableArray arrayWithArray:array];
NSLog(@"MutableArray:%@",MutableArray);
array1 = [NSArray arrayWithArray:array];
NSLog(@"array1:%@",array1);
//Copy
//id obj;
NSMutableArray *newArray = [[NSMutableArray alloc] init];
NSArray *oldArray = [NSArray arrayWithObjects:
                     @"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",nil];
NSLog(@"oldArray:%@",oldArray);
for(int i = 0; i < [oldArray count]; i++)
{
    obj = [[oldArray objectAtIndex:i] copy];
    [newArray addObject: obj];
}
//
NSLog(@"newArray:%@", newArray);
[newArray release];
快速遍历数组

//NSMutableArray *newArray = [[NSMutableArray alloc] init];
NSArray *oldArray = [NSArray arrayWithObjects:
                     @"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",nil];
NSLog(@"oldArray:%@",oldArray);
for(id obj in oldArray)
{
    [newArray addObject: obj];
}
//
NSLog(@"newArray:%@", newArray);
[newArray release];
Copy and sort
//NSMutableArray *newArray = [[NSMutableArray alloc] init];
NSArray *oldArray = [NSArray arrayWithObjects:
                     @"b",@"a",@"e",@"d",@"c",@"f",@"h",@"g",nil];
NSLog(@"oldArray:%@",oldArray);
NSEnumerator *enumerator;
enumerator = [oldArray objectEnumerator];
id obj;
while(obj = [enumerator nextObject])
{
    [newArray addObject: obj];
}
[newArray sortUsingSelector:@selector(compare:)];
NSLog(@"newArray:%@", newArray);
[newArray release];
NSMutableArray
给数组分配容量

//NSArray *array;
array = [NSMutableArray arrayWithCapacity:20];
在数组末尾添加对象

//- (void) addObject: (id) anObject;
//NSMutableArray *array = [NSMutableArray arrayWithObjects:
@"One",@"Two",@"Three",nil];
[array addObject:@"Four"];
NSLog(@"array:%@",array);
删除数组中指定索引处对象

//-(void) removeObjectAtIndex: (unsigned) index;
//NSMutableArray *array = [NSMutableArray arrayWithObjects:
@"One",@"Two",@"Three",nil];
[array removeObjectAtIndex:1];
NSLog(@"array:%@",array);
数组枚举

从前向后

//NSMutableArray *array = [NSMutableArray arrayWithObjects:
@"One",@"Two",@"Three",nil];
NSEnumerator *enumerator;
enumerator = [array objectEnumerator];
id thingie;
while (thingie = [enumerator nextObject]) {
    NSLog(@"thingie:%@",thingie);
}
从后向前

NSMutableArray *array = [NSMutableArray arrayWithObjects:
                         @"One",@"Two",@"Three",nil];
NSEnumerator *enumerator;
enumerator = [array reverseObjectEnumerator];
id object;
while (object = [enumerator nextObject]) {
    NSLog(@"object:%@",object);
}
快速枚举

//NSMutableArray *array = [NSMutableArray arrayWithObjects:
@"One",@"Two",@"Three",nil];
for(NSString *string in array)
{
    NSLog(@"string:%@",string);
}
NSDictionary
创建字典

//- (id) initWithObjectsAndKeys;
ctionary *dictionary = [[NSDictionary alloc] initWithObjectsAndKeys:@"One",@"1",@"Two",@"2",@"Three",@"3",nil];
NSString *string = [dictionary objectForKey:@"One"];
NSLog(@"string:%@",string);
NSLog(@"dictionary:%@",dictionary);
[dictionary release];
练习题：将文本“成绩单.text”内容加载到内存中并按规定的格式输出出来

NSMutableDictionary

创建

NSMutableDictionary *dictionary = [NSMutableDictionary dictionary];
添加字典

[dictionary setObject:@"One" forKey:@"1"];
[dictionary setObject:@"Two" forKey:@"2"];
[dictionary setObject:@"Three" forKey:@"3"];
[dictionary setObject:@"Four" forKey:@"4"];
NSLog(@"dictionary:%@",dictionary);
删除指定的字典

[dictionary removeObjectForKey:@"3"];
NSLog(@"dictionary:%@",dictionary);
NSValue（对任何对象进行包装）

将NSRect放入NSArray中

NSMutableArray *array = [[NSMutableArray alloc] init];
NSValue *value;
CGRect rect = CGRectMake(0, 0, 320, 480);
value = [NSValue valueWithBytes:&rect objCType:@encode(CGRect)];
[array addObject:value];
NSLog(@"array:%@",array);
从Array中提取

value = [array objectAtIndex:0];
[value getValue:&rect];
NSLog(@"value:%@",value);
定义结构体并添加到NSArray里面

typedef struct {
    float real;
    float imaginary;
} ImaginaryNumber;
ImaginaryNumber miNumber;
miNumber.real = 1.1;
miNumber.imaginary = 1.41;
NSValue *miValue = [NSValue value:miNumber
                     withObjCType:@encode(ImaginaryNumber)]; // encode using the type name
ImaginaryNumber miNumber2;
[miValue getValue:&miNumber2];