(转自：http://www.cocoachina.com/iphonedev/sdk/2010/0607/1634.html)
//一、NSString
/*----------------创建字符串的方法----------------*/
//1、创建常量字符串。
NSString *astring = @"This is a String!";
//2、创建空字符串，给予赋值。
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、用标准c创建字符串:initWithCString方法
char *Cstring = "This is a String!";
NSString *astring = [[NSString alloc] initWithCString:Cstring];
NSLog(@"astring:%@",astring);
[astring release];
//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];
//6、创建临时字符串
NSString *astring;
astring = [NSString stringWithCString:"This is a temporary string"];
NSLog(@"astring:%@",astring);
/*----------------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----------------*/
//用C比较:strcmp函数
char string1[] = "string!";
char string2[] = "string!";
if(strcmp(string1, string2) = = 0)
{
NSLog(@"1");
}
//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);
//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)
//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)
//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。
/*----------------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];
/*----------------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);
//扩展路径
NSString *Path = @"~/NSData.txt";
NSString *absolutePath = [Path stringByExpandingTildeInPath];
NSLog(@"absolutePath:%@",absolutePath);
NSLog(@"Path:%@",[absolutePath stringByAbbreviatingWithTildeInPath]);
//文件扩展名
NSString *Path = @"~/NSData.txt";
NSLog(@"Extension:%@",[Path pathExtension]);
/*******************************************************************************************
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);
/*--------将已有的空符串换成其它的字符串------*/
//-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);
/*-------------判断字符串内是否还包含别的字符串(前缀，后缀)-------------*/
//01： 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");
//02： 查找字符串某处是否包含其它字符串 - (NSRange) rangeOfString: (NSString *) aString，这一点前面在串中搜索子串用到过;
/*******************************************************************************************
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]);
//- (id) objectAtIndex: (unsigned int) index;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(可变数级)----------------------------*/
//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];
//快速枚举
//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];
//Deep copy
//NSMutableArray *newArray = [[NSMutableArray alloc] init];
NSArray *oldArray = [NSArray arrayWithObjects:
@"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",nil];
NSLog(@"oldArray:%@",oldArray);
newArray = (NSMutableArray*)CFPropertyListCreateDeepCopy(kCFAllocatorDefault, (CFPropertyListRef)oldArray, kCFPropertyListMutableContainers);
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];
/*--------------------------- 切分数组------------------------------*/
//从字符串分割到数组－ componentsSeparatedByString:
NSString *string = [[NSString alloc] initWithString:@"One,Two,Three,Four"];
NSLog(@"string:%@",string);
NSArray *array = [string componentsSeparatedByString:@","];
NSLog(@"array:%@",array);
[string release];
//从数组合并元素到字符串- componentsJoinedByString:
NSArray *array = [[NSArray alloc] initWithObjects:@"One",@"Two",@"Three",@"Four",nil];
NSString *string = [array componentsJoinedByString:@","];
NSLog(@"string:%@",string);
/*******************************************************************************************
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---------------*/
//- (NSEnumerator *)objectEnumerator;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);
}
//- (NSEnumerator *)reverseObjectEnumerator;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;
//NSDictionary *dictionary = [[NSDictionary alloc] initWithObjectsAndKeys:@"One",@"1",@"Two",@"2",@"Three",@"3",nil];
NSString *string = [dictionary objectForKey:@"One"];
NSLog(@"string:%@",string);
NSLog(@"dictionary:%@",dictionary);
[dictionary release];
/*******************************************************************************************
NSMutableDictionary
*******************************************************************************************/
/*------------------------------------创建可变字典 ------------------------------------*/
//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 ------------------------------------*/
//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);
/*******************************************************************************************
从目录搜索扩展名为jpg的文件
*******************************************************************************************/
//NSFileManager *fileManager = [NSFileManager defaultManager];
NSString *home;
home = @"../Users/";
NSDirectoryEnumerator *direnum;
direnum = [fileManager enumeratorAtPath: home];
NSMutableArray *files = [[NSMutableArray alloc] init];
//枚举
NSString *filename;
while (filename = [direnum nextObject]) {
if([[filename pathExtension] hasSuffix:@"jpg"]){
[files addObject:filename];
}
}
//快速枚举
//for(NSString *filename in direnum)
//{
// if([[filename pathExtension] isEqualToString:@"jpg"]){
// [files addObject:filename];
// }
//}
NSLog(@"files:%@",files);
//枚举
NSEnumerator *filenum;
filenum = [files objectEnumerator];
while (filename = [filenum nextObject]) {
NSLog(@"filename:%@",filename);
}
来源：https://www.cnblogs.com/imlucky/archive/2012/09/25/2701957.html