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*********字符串**********
*************************
1、固定字符串
1.初始化
NSString * str = @"kermit";
char * cStr = "中文";
NSString * str1 = [[NSString alloc] initWithCString:cStr encoding: NSUTF8StringEncoding];
NSString * str2 = [[NSString alloc] initWithFormat:@"format,%@ %d",@"字符串",10];
2.获取字符串长度
NSUInteger length = [str length];
3.获取单个字符
unichar ch = [str characterAtIndex:i];//打印unichar格式符 "%C"
4.获取子串
NSString substr = [str substringFromIndex:i]; //从索引值i开始截取到str的最后，存入substr（包含索引值）
NSString substr2 = [str substringToIndex:i]; //从str的第一个元素开始截取到i，存入substr（不包含索引值元素）
NSRange range = {a,b}; //NSUInteger location(range.location == a) 起始位置 NSUInteger length(range.length == b) 截取的长度
5.根据字符串，获得该字符串在另一个字符串中的索引范围
NSString * str = @"kermit";
NSString * str2 = @"www.kermit.com";
NSRange range = [str2 rangeOfString:str];
6.判断字符串是否为空
NSString * str = @""; //[str length] == 0; 为空
NSString * str1 = nil; //str == nil; 为空
NSString * str2 = @" "; //str == ' ';含有字符空格，不为空
7.判断是否以指定格式开头，或结尾
NSString * str = @"www.baidu.com";
NSString * str1 = @"hello.c";
BOOL hasPre = [str hasPrefix:@"www."]; //判断是否是网址 返回值BOOL类型
BOOL hasSuf = [str1 hasSuffix:@".c"]; //判断是否是 .c 文件
8.判断两个字符串是否相等
NSString * str = @"kermit";
NSString * str1 = @"kermit";
//方法一
if ([str isEqualToString:str1]) {
NSLog(@"==");
} else {
NSLog(@"!=");
}
//方法二
NSComparisonResult result = [str compare:str1]; //compare比较的时ASCII
switch (result) {
case NSOrderedAscending:
NSLog(@"<");
break;
case NSOrderedDescending:
NSLog(@">");
break;
case NSOrderedSame:
NSlog(@"==");
break;
}
9. int/float/double/char ---> NSString (多个数据拼接成一个字符串 @"%d%f%c%@" )
int a = 3;
float b = 3.14;
double c = 3.141592654321;
char d = 'm';
NSString * str = [[NSString alloc] initWithFormat:@"%d %.2f %.5f %C",a,b,c,d];
// str == @"33.143.141592654321m";
10. NSString ---> int/float/double //要保证字符串中的字符能正确转换成指定格式 eg: [@"3.14" intValue] 失败
NSStrig * str = @"100";
int a = [str intValue];
NSString * str1 = @"3.14";
float b = [str1 floatValue];
NSString * str2 = @"3.141592654321";
double c = [str2 doubleValue];
11.大小写转换（因为原字符串是不可变,所以要用一个新的字符串（不可变）去接收）
NSString * str = @"kermit";
NSString * str1 = @"kermit";
NSString * str00 = [str uppercaseString];
NSString * str10 = [str lowercaseString];
//首字母大写（被转换字母全部是大写，输出依旧是首字母大写,若字符串中含有空格，则空格后的第一个字母也是大写）
NSString * str100 = [@"kermit" capitalizedString]; //输出 "kermit"
NSString * str3 = @"bei jing me you";
NSString * str30 = [str3 capitalizedString]; //输出 “Bei Jing Me You"
12.在字符串末尾追加新的字符 (新字符串去接收)
NSString * str = @"kermit";
NSString * str1 = [str stringByAppendingString:@".com"]; //末尾只能追加固定内容的字符或字符串
13.在指定范围添加（覆盖）新的字符串
NSRange range = {4,0}; //追加在 range.location 处
NSRange range1 = {4,1}; //追加在 range1.location 处,覆盖长度 range.length 注意：覆盖的长度不能大于range1.location后面剩余的长度
NSString * str = @"www..com";
NSString * str2 = [str stringByReplacingCharacterInRange:range WithString: @"baidu"];
14.使用新的字符串替换原有的字符串
NSString * str = @"www.kermit.com";
NSString * str2 = [str stringByReplacingOccurencessOfString:@"kermit" withString:@"baidu"];
//删除字符串中的空格
NSString * str = @"ai wq ao mng";
NSString * str1 = [str stringByReplacingOccurencessOfString:@" " withString:@""];
15.字符串在文件中的读写
//写入文件
NSString * str = @"你好，世界。hello world.";
NSString * path = @"@"/Users/kermit/Desktop/未命名文件夹/str.txt"";
NSError * error;
//writeToFile:(NSString *) atomically:(BOOL) encoding:(NSStringEncoding) error:(NSError *__autoreleasing *)
[str writeToFile:path atomically:YES encoding:NSUIT8StringEncoding error:&error];
if (error) {
NSLog(@"写入失败",error);
} else {
NSLog(@"成功");
}
//读取字符串
NSString * str1 = [[NSString alloc] initWithContentsOfFile:path encoding:NSUTF8StringEncoding error:&error];
if (error == nil) {
NSLog(@"%@",str);
} else {
NSLog(@"%@",error);
}
2、可变字符串
1.初始化
NSString * str = @"nutable str";
NSMutableString * muStr = [[NSMutableString alloc] initWithString:str]; //muStr == @"mutable str";
2.重置字符串
NSMutableString * muStr1 = [[NSMutableString alloc] init];
[muStr1 setString:@"kermit"]; //muStr1 == @"kermit";
[muStr setString:@"kermit"]; //muStr == @"kermit";
3.在末尾追加字符串
[muStr1 appendString:@".com"]; //muStr1 == @"kermit.com";
[muStr1 appendingFormat:@"%@%d%.2f",@"abc",5,2.3]; //muStr1 == @"kermit.comabc52.30";
4.在指定位置插入字符串
[muStr1 insertString:@"www." atIndex:0]; //muStr1 == @"www.kermit.comabc52.30";
5.删除字符串(指定位置)
NSRange range = {12,4}; //.com
[muStr1 deleteCharacterInRange:range]; //muStr1 == @"www.kermitabc52.30";
*************************
**********数组************
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1、固定数组
1.创建数组(不可变数组创建后不可变，在创建的时候要初始化)
//对象方法 [[NSArray alloc] initWithObjects:(id),nil]
NSArray * array = [[NSArray alloc] initWithObjects:@"one",@"2",@"2.3",@"a",nil]; //array == (one,2,"2.3",a);
//类方法 [NSArray arrayWithObjects:(id),nil]
NSArray * array1 = [NSArray arrayWithObjects:@"one",@"2",@"2.3",@"a",nil]; //array == (one,2,"2.3",a);
//次方法最后一个元素必须是nil，如果数组中间存在 nil 元素，容易导致数据丢失
NSString * str = nil;
NSArray * array4 = [[NSArray alloc] initWithObjects:@"oe",@"2",str,@"t3",@"3.14", nil]; //array4 = (oe,2);
//快速方法 @[(id)]
NSArray * array3 = @[@"one#",@"23",@"2.3",@"a"]; //array = ("one#",23,"2.3",a);
2.基本类型转换成数组对象
//数组中可以存储不同类型的对象
int i = 10;
float f = 3.14;
NSNumber * number = [NSNumber numberWithInt:i];
NSNumber * number1 = [NSNumber numberWithFloat:f];
NSArray * array = @[@"one",@"10",number,number1]; // array == (one,10,10,"3.14");
//数组中存储的是对象的地址，数组中也可以存储数组的地址
NSArray * array1 = @[@"1",@"2",@"3"];
NSArray * array2 = @[array,array1];
3.数组中自定义对象
//创建三个对象（类以及创建）
Person * p1 = [[Person alloc] initWithName:@"Jack" andAge:15];
Person * p2 = [[Person alloc] initWithName:@"Tom" andAge:20];
Person * p3 = [[Person alloc] initWithName:@"Lucy" andAge:18];
NSArray array4 = @[p1,p2,p3];
4.获取数组中的元素
Person * p = [array4 objectAtIndex:0]; //name = Jack,age = 15
Person * p = array4[0]; //快速方法
5.数组中元素个数
NSUInteger count = [array4 count];
NSLog(@"%lu",count);
6.判断数组中是否包含某个元素
Person * p4 = [[Person alloc] initWithName:@"Tom" andAge:20];
NSLog(@"p2=%p,p4=%p",p2,p4); //p2和p4的地址不相同，p4为新对象
if ([array4 containsObject:p4]) {
NSLog(@"包含");
} else {
NSLog(@"不包含");
}
//不包含，p4不在array4中，即使内容相同，但是也不包含
NSArray * array5 = @[@"one",@"two",@"three"];
NSString * str2 = @"one";
NSString * str4 = @"one";
NSString * str3 = [[NSString alloc] initWithFormat:@"%@",@"two"];
NSLog(@"%p %p %p %p",str2,str3,str4,array9[0]); //0x100002088 0x6f777435 0x100002088
//在创建字符串的时候会判断内存是否含有相同字符串，若有相同的则不会新开辟内存去存储，只把新的字符串指针指向那个地址，若没有相同的则就会新开辟空间去存储
//但是 str3 是重新初始化 NSString，所以str3的地址是固定的 并不和array[1]的地址一样
if ([array9 containsObject:str3]) {
NSLog(@"包含");
} else {
NSLog(@"不包含");
}
//包含
7.遍历数组
NSArray * array = @[@"1",@"2",@"three",@"4"];
//方法一
for (int i=0; i<[array count]; i++) {
NSLog(@"array[%d]=%@",i,array[i]);
}
//方法二
for (id * str in array) {
NSLog(@"%@",str);
}
8.数组排序(排序后放在一个新的NSArray数组中)
NSArray * array = @[@"a",@"b",@"f",@"d",@"c"];
//传入一个比较大小的方法 根据返回值来决定是否需要交换元素
NSArray * array2 = [array sortedArrayUsingSelect:sel];
SEL sel = @selector(compare:); //a-b-c-d-f
SEL sel2 = @selector(isGreatThan:); //a-b-c-d-f
SEL sel3 = @selector(isLessThan:); //f-d-c-b-a
//block
//返回值 (^名字)(参数列表)
NSArray * array3 = [array sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
return [obj1 compare:obj2];
}]; //a-b-c-d-f
NSArray * array4 = [array sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
return [obj1 compare:obj2];
}]; //f-d-c-b-a
2、可变数组
1.创建可变数组
NSArray * array = @[@"one",@"two",@"three",@"four"];
NSMutableArray * muArr = [[NSMutableArray alloc] initWithArray:array];
NSMutableArray * muArr2 = [NSMutableArray arrayWithObjects:@"one",@"two",@"three",nil];
2.添加元素
NSMutableArray * muArr3 = [[NSMutableArray alloc] init];
[muArr3 addObject:@"one"];
3.添加其他数组的元素
[muArr3 addObjectsFromArray:array];
4.在指定位置插入元素
[muArr3 insetObject:@"a" atIndex:1];
5.删除元素 会通过对象地址删除数组中所有的用同一个地址的对象
[muArr removeObject:@"one"]; //删除数组中的所有指向"one"地址的元素
6.通过索引方式删除对象(索引值不能数组越界)
[muArr removeObjectAtIndex:0];
7.删除所有元素
[muArr removeAllObjects];
8.交换数组元素 //- (void)exchangeObjectAtIndex:(NSUInteger)idx1 withObjectAtIndex:(NSUInteger)idx2;
[muArr exchangeObjectAtIndex:i withObjectAtIndex:j]
3、数组转换
1.不可变数组到可变数组
NSArray * array = @[@"one",@"two"];
NSMutableArray * muArr = [[NSMutableArray alloc] initWithArray:array]; // [array mutableCopy];
2.可变数组变成不可变数组
[muArr copy]
*************************
**********字典************
*************************
1、不可变字典
1.创建不可变字典
NSDictionary * dic = [[NSDictionary alloc] initWithObjectsAndKeys:@"one",@"1",@"two",@"2",nil];
//快速创建字典
NSDictionary * dic1 = @{@"3":@"three",@"4":@"four"};
2.字典可以存储任意类型的对象
NSArray * array = @[@"one",@"333"];
NSNumber * num = [NSNumber numberWithInt:10];
NSDicitonary * dic2 = @{@"dic":dic,@"num":num,@"array":array};
3.获取字典的长度(键的个数)
NSUInteger count = [dic2 count];
4.从字典中取值
NSString * arr = [dic3 objectForKey:@"array"];
//快速取值
NSDictionary * dic4 = dic3[@"dic"];
NSNumber * number = dic3[@"num"];
2、可变字典
1.创建可变字典
NSMutableDictionary * muDic = [[NAMutableDictionary alloc] initWithObjectsAndKeys:@"one",@"1",nil];
//向可变字典中添加不可变字典
NSDictionary * dic = @{@"3":@"three"};
NSMutableDictionary * muDic2 = [[NSMutableDictionary alloc] initWithDictionary:dic];
2.向字典中插入数据
[muDic2 setObject:@"two" forKey:@"2"];
3.遍历字典
NSArray * allKeys = [muDic2 allKeys];
for (id key in allKeys) {
NSLog(@"%@",key);
id obj = muDic2[key];
NSLog(@"%@",obj);
}
4.删除数据
[muDic2 removeObjectForKey:@"2"];
5.全部删除
[muDic removeAllObjects];
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**********集合************
*************************
//NSSet 是无序的，不能存储重复数据，可以用来去除重复数据
//NSArray 是自然顺序
1、不可变集合
1.创建
NSSet * set = [[NSSet alloc] initWithObjects:@"one",@"b",@"two",@"three",@"a"@"two",nil];
2.个数
NSUInteger count = [set count];
3.判断是否包含某个对象
BOOL isContation = [set contationObject:@"t"];
if (isContation) {
NSLog(@"contation");
} else {
NSLog(@"not contation");
}
2、可变集合
1.创建
NSMutableSet * muSet = [[NSMutableSet alloc] initWithObjects:@"1",@"2",@"3",nil];
2.添加对象
[muSet addObject:@"four"];
3.删除对象
[muSet removeObject:@"2"];
4.删除所有对象
[muSet removeAllObjects];
*************************
********相互转换**********
*************************
1.数组-->集合
NSSet * set = [[NSSet alloc] initWithArray:array];
2.字典-->数组
NSDictionary * dic = @{@"1":@"two",@"2":@"kk"};
NSArray * keysArr = [dic allKeys];
NSArray * valuaesArr = [dic allValues];
3.字符串-->数组
NSString * str = @"I am in shanghai";
NSArray * strArr = [str componentsSeparatedByString:@" "];
4.数组-->字符串
NSString * str1 = [strArr componentsJoinedByString:@"-"];
