iOS基础：NSString常用方法

#pragma mark - 1、字符串的初始化-(void)initStringFun{    //1、使用Unicode数值数组转化成字符串    unichar data[6] = {97,98,99,100,101,102};    NSString * string = [[NSString alloc] initWithCharacters:data length:6];    NSLog(@"string = %@",string);    NSString * str = [NSString stringWithCharacters:data length:6];    NSLog(@"str = %@",str);        //2、将c风格字符串转NSString对象    char * cStr = "hello,iOS";    NSString * cString = [[NSString alloc] initWithUTF8String:cStr];    NSLog(@"cString = %@",cString);        //将oc字符串转为c字符串    const char * strToC = [cString UTF8String];    NSLog(@"strToC = %s",strToC);    }

#pragma mark - 2、字符串的常用功能-(void)commonFunction{    //1、追加字符串    NSString * str = @"Hello";    NSString * book = @",book";    NSString * strBook = [str stringByAppendingString:book];    NSLog(@"str = %@",str);    NSLog(@"strBook = %@",strBook);        //2、追加带变量的字符串    NSString * fStr = @"Hello";    NSString * formatStr = [fStr stringByAppendingFormat:@",%@Book",@"Good"];    NSLog(@"fStr = %@",fStr);    NSLog(@"formatStr = %@",formatStr);        //3、字符串的截取    NSString * string = @"hello,this is a good book";    NSString * subStr1 = [string substringToIndex:10];//0-10的子字符串    NSString * subStr2 = [string substringFromIndex:10];//10-末尾的子字符串    NSString * subStr3 = [string substringWithRange:NSMakeRange(2, 3)];//2开始的3个字符长度的字符串    NSLog(@"subStr1 = %@",subStr1);    NSLog(@"subStr2 = %@",subStr2);    NSLog(@"subStr3 = %@",subStr3);        //4、子字符串所在位置及长度    NSString * mainString = @"hello,world";    NSString * subStr = @"world";    NSRange range = [mainString rangeOfString:subStr];    NSLog(@"range.location = %ld,range,length = %ld",range.location,range.length);        //5、字符串统一转大小写    NSString * smallBigStr = @"Hello,World";    NSString * smallStr = [smallBigStr lowercaseString];    NSString * bigStr = [smallBigStr uppercaseString];    NSLog(@"smallStr = %@",smallStr);    NSLog(@"bigStr = %@",bigStr);        //6、字符串前后缀    NSString * preString = @"hello,world";    BOOL hasPre = [preString hasPrefix:@"hello"];    NSLog(@"hasPre = %d",hasPre);    NSString * sufString = @"hello,world";    [sufString hasSuffix:@"world"];    NSLog(@"sufString = %d",hasPre);        //7、字符串长度    NSString * lengthStr = @"hello,world";    NSLog(@"lengthStr.length = %ld",lengthStr.length);        //8、字符串中的字符    NSString * charStr = @"hello,world";    unichar c = [charStr characterAtIndex:0];    NSLog(@"c = %c",c);        //9、字符串的比较    NSString * compareStr1 = @"hello";    NSString * compareStr2 = @"world";    NSComparisonResult result = [compareStr1 compare:compareStr2];    NSLog(@"result = %d",result);        BOOL isEqual = [compareStr1 isEqualToString:compareStr2];    NSLog(@"isEqual = %d",isEqual);        //10、字符串的分割    NSString * sepStr = @"hello-world";    NSArray * setArray = [sepStr componentsSeparatedByString:@"-"];    NSLog(@"setArray = %@",setArray);        NSCharacterSet * charSet = [NSCharacterSet characterSetWithCharactersInString:@"-o"];    NSArray * array = [sepStr componentsSeparatedByCharactersInSet:charSet];    NSLog(@"array = %@",array);}

#pragma mark - 3、可变字符串-(void)mutableStringFun{    NSMutableString * mString = [[NSMutableString alloc] initWithString:@"hello"];    //1、追加字符串    [mString appendString:@",book"];    NSLog(@"mString = %@",mString);        //2、追加带变量的字符串    [mString appendFormat:@".%@ Good Book",@"This Is A"];    NSLog(@"mString = %@",mString);        //3、删除指定位置字符    [mString deleteCharactersInRange:NSMakeRange(0, 6)];    NSLog(@"mString = %@",mString);        //4、替换指定位置字符    [mString replaceCharactersInRange:NSMakeRange(0, 6) withString:@"你好"];    NSLog(@"mString = %@",mString);        //5、在指定位置插入字符    [mString insertString:@"你好" atIndex:7];    NSLog(@"mString = %@",mString);        //6、覆盖字符串    [mString setString:@"你好，世界"];    NSLog(@"mString = %@",mString);       }

#pragma mark - 4、其它方法//将int类型 转为16进制的字符串1-(void)hexStringFromNum{    int num = 16;    NSString *hexString = [NSString stringWithFormat:@"%@",[[NSString alloc] initWithFormat:@"%1x",num]];    NSLog(@"hexString = %@",hexString);}//将int类型 转为16进制的字符串2(待验证)-(void)longlongToHexStr{    NSInteger value = 16;    int len = 2;    char ASSICCHAR[] = "0123456789ABCDEF";;    char resultBuffer[len];    for (int i = 0; i < len; i++) {        resultBuffer[len - i - 1] = ASSICCHAR[(value >> (i * 4)) & 0x0F];    }    NSString * hexString = [NSString stringWithCString:resultBuffer encoding:NSASCIIStringEncoding];    NSLog(@"hexString = %@",hexString);}//字典转为json格式字符串-(NSString*)jsonStringFromDict{    NSDictionary * dict = @{@"1":@"test1",                            @"2":@"test3"};    NSData * mData = [NSJSONSerialization dataWithJSONObject:dict options:NSJSONWritingPrettyPrinted error:nil];    NSString * dictString = [[NSString alloc] initWithData:mData encoding:NSUTF8StringEncoding];    NSLog(@"dictString = %@",dictString);    return dictString;}//将json格式字符串转为字典-(NSDictionary *)parseJSONStringToNSDictionary{    NSString * JSONString = [self jsonStringFromDict];    //将字符串转成二进制数据    NSData *JSONData = [JSONString dataUsingEncoding:NSUTF8StringEncoding];    //利用系统自带的JSON解析，解析成字典格式    NSDictionary *responseJSON = [NSJSONSerialization JSONObjectWithData:JSONData options:NSJSONReadingMutableLeaves error:nil];    //将字典返回    NSLog(@"responseJSON = %@",responseJSON);    return responseJSON;}//去掉非数字字符-(void)removeUnnumberChar{    NSString * number = @"156-8888-8888";    //invertedset:为翻转    NSCharacterSet *setToRemove = [[ NSCharacterSet characterSetWithCharactersInString:@"0123456789"] invertedSet];    NSArray * numArray = [number componentsSeparatedByCharactersInSet:setToRemove];    NSLog(@"numArray = %@",numArray);    NSString *phoneStr = [numArray componentsJoinedByString:@""];}

//字符串与int类型互转-(void)stringToInt{        //数字转字符串    int num = 12;    NSString * intString = [NSString stringWithFormat:@"%d",num];    NSLog(@"intString = %@",intString);        //字符串转数字    NSString * string = @"12";//会转为12；类似@”我“这样的非数字的字符串会转为0    NSInteger stringInt = [string integerValue];    NSLog(@"stringInt = %ld",stringInt);}

//字符串与data互转-(void)stringToData{    //把字符串再转变为二进制流    NSString * string = @"I have a dream";    NSData * data=[NSMutableData dataWithData:[string dataUsingEncoding:NSUTF8StringEncoding]];    NSLog(@"data = %@",data);        //二进制流转变为字符串    NSString * dataStr=[[NSMutableString alloc] initWithData:data encoding:NSUTF8StringEncoding];    NSLog(@"dataStr = %@",dataStr);}