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你遗忘的都在这里—iOS常用类型方法笔记

2016-05-05 15:56 162 查看

　　这些都是项目中常用但又常忘的方法，与大家分享一下。

一、NSString

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);

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);

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];

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);

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;
//- (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);

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);

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);
}

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);

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];

四、宏定义#define讲解

NSNumber

+ (NSNumber *)numberWithInt:(int)value;
+ (NSNumber *)numberWithDouble:(double)value;
- (int)intValue;
- (double)doubleValue;

NSNumber可以将基本数据类型包装起来，形成一个对象，这样就可以给其发送消息，装入NSArray中等等。

NSNumber * intNumber=[NSNumber numberWithInt：100]；
NSNumber *floatNumber=[NSNUmber numberWithFloat:100.00];
int i=[intNumber intValue]；
if([intNumber isEqualToNumber:floatNumber]) ....

NSNumber继承NSObject ，可以使用比较 compare： isEqual等消息

NSNull

IOS里面最小简单的类，里面只有一个方法+(NSNull*) null;

数学常用方法

数学常量：

#define M_E         2.71828182845904523536028747135266250   // e
#define M_LOG2E     1.44269504088896340735992468100189214   // log 2e
#define M_LOG10E    0.434294481903251827651128918916605082  // log 10e
#define M_LN2       0.693147180559945309417232121458176568  // log e2
#define M_LN10      2.30258509299404568401799145468436421   // log e10
#define M_PI        3.14159265358979323846264338327950288   // pi
#define M_PI_2      1.57079632679489661923132169163975144   // pi/2
#define M_PI_4      0.785398163397448309615660845819875721  // pi/4
#define M_1_PI      0.318309886183790671537767526745028724  // 1/pi
#define M_2_PI      0.636619772367581343075535053490057448  // 2/pi
#define M_2_SQRTPI  1.12837916709551257389615890312154517   // 2/sqrt(pi)
#define M_SQRT2     1.41421356237309504880168872420969808   // sqrt(2)
#define M_SQRT1_2   0.707106781186547524400844362104849039  // 1/sqrt(2)

常用函数：

指数运算

NSLog(@"%.f", pow(3,2) ); //result 9
NSLog(@"%.f", pow(3,3) ); //result 27

开平方运算（计算两点间的距离时用到）

NSLog(@"%.f", sqrt(16) ); //result 4
NSLog(@"%.f", sqrt(81) ); //result 9

上舍入

NSLog(@"res: %.f", ceil(3.000000000001)); //result 4
NSLog(@"res: %.f", ceil(3.00)); //result 3

下舍入

NSLog(@"res: %.f", floor(3.000000000001)); //result 3
NSLog(@"res: %.f", floor(3.9999999)); //result 3

四舍五入

NSLog(@"res: %.f", round(3.5)); //result 4
NSLog(@"res: %.f", round(3.46)); //result 3
NSLog(@"res: %.f", round(-3.5)); //NB: this one returns -4

最小值

NSLog(@"res: %.f", fmin(5,10)); //result 5

最大值

NSLog(@"res: %.f", fmax(5,10)); //result 10

绝对值

NSLog(@"res: %.f", fabs(10)); //result 10
NSLog(@"res: %.f", fabs(-10)); //result 10

NSDate

得到当前的日期

NSDate *date = [NSDate date];

日期之间比较可用以下方法

- (BOOL)isEqualToDate:(NSDate *)otherDate;// 与otherDate比较，相同返回YES
- (NSDate *)earlierDate:(NSDate *)anotherDate;// 与anotherDate比较，返回较早的那个日期
- (NSDate *)laterDate:(NSDate *)anotherDate;//与anotherDate比较，返回较晚的那个日期

将日期转换成字符串

NSLog(@”date = %@”,[data description]);

设置日期显示格式

NSDateFormatter *formatter =[[[NSDateFormatter alloc] init] autorelease];
[formatter setTimeStyle:NSDateFormatterFullStyle]; //设置几种默认的显示效果
[formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss a"];//设置自定义的显示效果
NSLog([formatter stringFromDate:date]);

NSData

//NSData－> NSString
NSString *aString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
//NSString－>NSData
NSString *aString = @"1234abcd";
NSData *aData = [aString dataUsingEncoding: NSUTF8StringEncoding];

NSString和Time

// 创建字符串
- (void)CreatString
{
// <1> 创建字符创
NSString *strS = @"This is a String!";

// <2> 创建空字符串,给予赋值
NSString *strK = [[NSString alloc] init];

strK = @"This is a String!";

NSLog(@"strS:%@, strK%@",strS,strK);

// <3> 使用变量初始化字符串
NSString *name = @"aofe";

NSString *strN = [NSString stringWithFormat:@"My name is %@",name];

NSLog(@"strN:%@",strN);
}

// 判断是否包含某字符串
- (void)IsContainsString
{
NSString *str1 = @"NSStringInformation.txt";

// <1> 检查字符串是否以另一个字符串开头
[str1 hasPrefix:@"NSString"] == 1? NSLog(@"YES") :NSLog(@"NO");

// <2> 检查字符串是否以另一个字符串结尾
[str1 hasSuffix:@".txt"] == 1? NSLog(@"YES") :NSLog(@"NO");

// <3> 检查字符串是否包含其他字符串
[str1 rangeOfString:@"Information"].length > 0 ? NSLog(@"YES") :NSLog(@"NO");

}

// 读写字符串
-(void)WriteAndReadString
{
// 文件路径
NSString *path = @"wenJianQuanLuJing";

// <1> 从文件读取字符串
NSString *strW = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:NULL];

// <2> 将字符串写入到文件
[strW writeToFile:path atomically:YES encoding:NSUTF8StringEncoding error:NULL];
}

// 比较两个字符串
-(void)ComparerTwoString
{
NSString *str1 = @"This is String1";

NSString *str2 = @"THIS is String2";

// 比较两个字符串是否相等
BOOL result1 = [str1 isEqualToString:str2];

// 比较两个字符串(comparer方法返回三种值:NSOrderedAscending = -1L, NSOrderedSame, NSOrderedDescending)

NSComparisonResult result2 = [str1 compare:str2];

// 不考虑大小比较字符串
NSComparisonResult result3 = [str1 caseInsensitiveCompare:str2];

NSLog(@"result1:%d,result2:%ld,result3:%ld",result1,(long)result2,(long)result3);

}

// 改变字符串的大小写
-(void)ChangeStringCase
{
NSString *str1 = @"this is string1";
NSString *str2 = @"THIS IS STRING2";

// 全部大写
[str1 uppercaseString];

// 全部小写
[str2 lowercaseString];

// 首字母大写
[str1 capitalizedString];
}

// 在字符串中搜索子串
-(void)SearchString
{
NSString *str1 = @"This is String1";
NSString *str2 = @"is";

NSRange range = [str1 rangeOfString:str2];

NSLog(@"location:%lu,length:%lu",(unsigned long)range.location,(unsigned long)
range.length);

}

// 替换字符串
-(void)ReplaceString
{
NSString *strL = @"hello china";

NSString *strN = [strL stringByReplacingOccurrencesOfString:@"china" withString:@"beijing"];

NSLog(@"strL:%@,strN:%@",strL,strN);
}

// 分隔字符串成数组
-(void)ComponentsString
{
NSString *str = @"a b c d e";
// 以空格分隔字符串成数组
NSArray *arr = [str componentsSeparatedByString:@" "];

NSLog(@"arr:%@,arr.count:%lu",arr,(unsigned long)arr.count);

}

// 数组拼接成字符串
-(void)ArrayToString
{
NSArray *array = [NSArray arrayWithObjects:@"this",@"is",@"String", nil];
// 用空格隔开数组中的元素
NSString *str = [array componentsJoinedByString:@" "];

NSLog(@"str:%@",str);
}

// 从字符串中抽取出新的字符串
-(void)DrawNewString
{
NSString *str = @"This is String";
// 从字符串的开头一直截取到指定位置,但不包括该位置的字符.
NSString *str1 = [str substringToIndex:5];

// 从指定位置开始(包括自定位置的字符串)一直到最后
NSString *str2 = [str substringFromIndex:5];

// 按照所给定的位置和长度,任意的从字符串中截取新的字符串
NSString *str3 = [str substringWithRange:NSMakeRange(4, 5)];

NSLog(@"str1:%@,str2:%@,str3:%@",str1,str2,str3);
}

// 可变字符串的操作
- (void)NSMutableStringOperation
{
// 给字符串分配容量
NSMutableString *strM = [NSMutableString stringWithCapacity:100];
NSLog(@"strM:%@",strM);

// 在已有的字符串后面添加字符串
NSMutableString *strM1 = [[NSMutableString alloc] initWithString:@"This is a"];
NSLog(@"strM1:%@",strM1);

[strM1 appendString:@"NSMutableString"];
NSLog(@"strM1:%@",strM1);

// 在已有字符串中按照所给出的范围和长度删除字符
[strM1 deleteCharactersInRange:NSMakeRange(0, 5)];
NSLog(@"strM1:%@",strM1);

// 在字符串指定位置插入字符串
[strM1 insertString:@"Hello" atIndex:0];
NSLog(@"strM1:%@",strM1);

// 将已有字符串替换成其他字符串
[strM1 setString:@"Hello World"];
NSLog(@"strM1:%@",strM1);

// 按照所给出的范围,用新字符串替换原来的字符串
[strM1 replaceCharactersInRange:NSMakeRange(0, 5) withString:@"Hi"];
NSLog(@"strM1:%@",strM1);
}

// 时间操作
- (void)NSDateOperation
{
// 得到当前日期
NSDate *date1 = [NSDate date];
NSLog(@"date:%@",date1);

NSDate *date2 = [NSDate dateWithTimeIntervalSinceNow:3];

// 比较日期:

// <1> 比较日期是否相同
BOOL result =[date1 isEqualToDate:date2];

// <2> 比较日期 返回时间较早的日期
NSDate *dateE = [date1 earlierDate:date2];

// <3> 比较日期 返回时间较晚的日期
NSDate *dateL = [date1 laterDate:date2];

NSLog(@"result:%d, dateE:%@, dateL:%@",result,dateE,dateL);

// 设置日期的格式
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];

// 设置几种默认的显示效果
[formatter setTimeStyle:NSDateFormatterMediumStyle];

//自定义日期显示效果
[formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

NSString *time = [formatter stringFromDate:date1];

NSLog(@"%@",time);

}

Math

// 常用常数
-(void)mathConstant
{
#define M_E         2.71828182845904523536028747135266250   /* e              */
#define M_LOG2E     1.44269504088896340735992468100189214   /* log2(e)        */
#define M_LOG10E    0.434294481903251827651128918916605082  /* log10(e)       */
#define M_LN2       0.693147180559945309417232121458176568  /* loge(2)        */
#define M_LN10      2.30258509299404568401799145468436421   /* loge(10)       */
#define M_PI        3.14159265358979323846264338327950288   /* pi             */
#define M_PI_2      1.57079632679489661923132169163975144   /* pi/2           */
#define M_PI_4      0.785398163397448309615660845819875721  /* pi/4           */
#define M_1_PI      0.318309886183790671537767526745028724  /* 1/pi           */
#define M_2_PI      0.636619772367581343075535053490057448  /* 2/pi           */
#define M_2_SQRTPI  1.12837916709551257389615890312154517   /* 2/sqrt(pi)     */
#define M_SQRT2     1.41421356237309504880168872420969808   /* sqrt(2)        */
#define M_SQRT1_2   0.707106781186547524400844362104849039  /* 1/sqrt(2)      */
}

// 常用函数
- (void)mathFunc
{
// <1> 指数运算
NSLog(@"%.f",pow(3, 2)); //9
NSLog(@"%.f",pow(2, 3)); //8

// <2> 开平方运算(计算两点之间的距离)
NSLog(@"%.f",sqrt(16)); // 4
NSLog(@"%.f",sqrt(81)); // 9

// <3> 四舍五入
NSLog(@"round:%.f",round( 3.5)); //  4
NSLog(@"round:%.f",round(-3.5)); // -4

// <4> 上舍入
NSLog(@"ceil:%f",ceil(3.00001)); // 4
NSLog(@"ceil:%f",ceil(3.00000)); // 3

// <5> 下舍入
NSLog(@"res:%f",floor(3.00001)); // 3
NSLog(@"res:%f",floor(3.99999)); // 3

// <6> 最小值
NSLog(@"min:%f",fmin(5, 10)); // 5

// <7> 最大值
NSLog(@"max:%f",fmax(11, 5)); // 11

// <8> 绝对值
NSLog(@"abs:%d",abs(-10)); // 10
NSLog(@"fabs:%f",fabs(-5.5)); // 5.5

}

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