NSData NSString 读写文件

遍历字典

    for (id key in paramValues_){
        NSLog(@"key: %@ ,value: %@",key,[paramValues_ objectForKey:key]);
    }
 


读写文件

NSString *path = @"/Users/Allen/Desktop/test.dat";
 
NSString *temp = @"Allen Dang";
int i = 100;
float f = 98.3333f;

NSMutableData *writer = [[NSMutableData alloc] init];
 
[writer appendData:[temp dataUsingEncoding:NSUTF8StringEncoding]];
[writer appendBytes:&i length:sizeof(i)];
[writer appendBytes:&f length:sizeof(f)];
 
[writer writeToFile:path atomically:YES];
[writer release];

 

读文件

NSString *contentPath = [[NSBundle mainBundle] pathForResource:@"Content" ofType:@"txt"];

    NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);

NSString *txtContent = [NSString stringWithContentsOfFile:contentPath encoding:NSUTF8StringEncoding error:nil];

 

 

写文件

NSString *str = @"asdasdads";

        NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);

        NSData *data = [str dataUsingEncoding:enc];

        NSString *filename = @"/Users/xxx/files.txt"];

        [data writeToFile: filename atomically: NO];






int ii;
float ff;
NSString *ttemp;
 
NSData *reader = [NSData dataWithContentsOfFile:path];
ttemp = [[NSString alloc] initWithData:[reader subdataWithRange:NSMakeRange(0, [temp length])]
                                  encoding:NSUTF8StringEncoding];
[reader getBytes:&ii range:NSMakeRange([temp length], sizeof(ii))];
[reader getBytes:&ff range:NSMakeRange([temp length] + sizeof(ii), sizeof(ff))];
 
NSLog(@"string:%@  int:%i float:%f", ttemp, ii, ff);
 
[temp release];
[ttemp release];
[path release];

NSString为UTF8编码的函数

@interface NSString (OAURLEncodingAdditions)

- (NSString *)URLEncodedString;

- (NSString *)URLDecodedString;

@end


@implementation NSString (OAURLEncodingAdditions)
- (NSString *)URLEncodedString{   
    NSString *result = (NSString *)CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault, (CFStringRef)self, NULL, CFSTR("!*'();:@&=+$,/?%#[]"), kCFStringEncodingUTF8);
   [result autorelease];
   return result;
}
- (NSString*)URLDecodedString{
   NSString *result = (NSString *)CFURLCreateStringByReplacingPercentEscapesUsingEncoding(kCFAllocatorDefault, (CFStringRef)self, CFSTR(""), kCFStringEncodingUTF8);
   [result autorelease];
   return result;
}
@end

 

 

 

 

 

NSString NSData 转换与常见的 NSString 和 NSMutableString 方法


NSString* aStr = [[NSString alloc] initWithData:aData encoding:NSASCIIStringEncoding];







NSData* aData = [aStr dataUsingEncoding: NSASCIIStringEncoding];




NSString方法
+(id) stringWithContentsOfFile:path encoding:enc error:err
创建一个新字符串并将其设置为path指定的文件的内容,使用字符编码enc,如果非零,则返回err中错误

+(id) stringWithContentsOfURL:url encoding:enc error:err
创建一个新的字符串,并将其设置为url的内容,使用字符编码enc,如果非零,则返回err中的错误

+(id) string
创建一个新的空字符串

+(id) stringWithString:nsstring
创建一个新的字符串,并将其设置为nsstring

-(id)initWithString:nsstring
将分配的字符串设置为nsstring

-(id) initWithContentsOfFile:path encoding:enc error:err
将字符串设置为path制定的文件的内容

-(id) initWithContentsOfURL:url encoding:enc error:err
将字符串设置为url(NSURL *)url的内容,使用字符编码enc,如果非零,则返回err中的错误

-(id) (UNSIgned int)length
返回字符串中的字符数目

-(unichar)characterAtIndex:i
返回索引i的Unicode字符

-(NSString *)substringFromIndex:i
返回从i开始知道结尾的子字符串

-(NSString *)substringWithRange:range
根据指定范围返回子字符串

-(NSString *)substringToIndex:i
返回从该字符串开始到索i的子字符串

-(NSComparator *)caseInsensitiveCompare:nsstring
比较两个字符串,忽略大小写

-(NSComparator *)compare:nsstring
比较两个字符串

-(BOOL)hasPrefix:nsstring
测试字符串是否以nsstring开始

-(BOOL)hasSuffix:nsstring
测试字符串是否以nsstrng结尾

-(BOOL)isEqualToString:nsstring
测试两个字符串是否相等

-(NSString *) capitalizedString
返回每个单词首字母大写的字符串(每个单词的其余字母转换为小写)

-(NSString *)lowercaseString
返回转换为小写的字符串

-(NSString *)uppercaseString
返回转换为大写的字符串

-(const char*)UTF8String
返回转换为UIF-8字符串的字符串

-(double)doubleValue
返回转换为double的字符串

-(float)floatValue
返回转换为浮点值的字符串

-(NSInteger)integerValue
返回转换为NSInteger整数的字符串

-(int)intValue
返回转换为整数的字符串

NSMutableString方法
+(id) stringWithCapacity:size
创建一个字符串,初始包含size的字符

-(id) initWithCapacity:size
使用初始容量为size的字符串来初始化字符串

-(void) setString:nsstring
将字符串设置为nsstring

-(void) appendString:nsstring
在接收者的末尾附加nsstring

-(void) deleteCharactersInRange:range
删除指定range中的字符

-(void) insertString:nsstring atIndex:i
以索引i为起始位置插入nsstring

-(void) replaceCharactersInRange:range withString:nsstring
使用nsstring替换range指定的字符

-(void) replaceOccurrencesOf
String:nsstring withString:nsstring2 options:opts range:range
根 据选项opts。使用指定range中的nsstring2替换所有的nsstring。选项可以包括NSBackwardsSearch(从范围的结尾 开始搜索)NSAnchoredSearch(nsstring必须匹配范围的开始),NSLiteralSearch(执行逐字节比较以及 NSCaceInsensitiveSearch的按位或组合)


*----------------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);







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