NSString 转换成NSData 对象
NSData* xmlData = [@"testdata" dataUsingEncoding:NSUTF8StringEncoding];
NSData 转换成NSString对象
NSData * data; NSString *result = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSData 转换成char*
NSData *data; char *test=[data bytes];
char* 转换成NSData对象
byte* tempData = malloc(sizeof(byte)*16); NSData *content=[NSData dataWithBytes:tempData length:16];
- NSString *tempA = @"123";
- NSString *tempB = @"456";
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1,字符串拼接
- NSString *newString = [NSString stringWithFormat:@"%@%@",tempA,tempB];
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2,字符转int
- int intString = [newString intValue];
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3,int转字符
- NSString *stringInt = [NSString stringWithFormat:@"%d",intString];
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4,字符转float
- float floatString = [newString floatValue];
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5,float转字符
- NSString *stringFloat = [NSString stringWithFormat:@"%f",intString];
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/字典或者数组转化为nsstring
NSArray *arr = [NSArray arrayWithObject:@"1"];
NSString *str = [arr JSONString]; //数组或者字典转化为json串
NSArray *arr1 = [str objectFromJSONString]; //json串转化为字典或者数组
NSData *data = [arr1 JSONData]; //把json串转化为nsdata
NSString *str1 = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
//把NSdata转为为NSString
NSData *data1 = [str1 dataUsingEncoding:NSUTF8StringEncoding]; //把NSString转化为NSData
//二进制流转变为字符串
NSString *str=[[NSMutableString alloc] initWithData:self.receiveDataencoding:NSUTF8StringEncoding];
//转变其中的内容
str=[str stringByReplacingOccurrencesOfString:@"," withString:@",\n"];
str=[str stringByReplacingOccurrencesOfString:@"{" withString:@"{\n"];
str=[str stringByReplacingOccurrencesOfString:@"}" withString:@"\n}"];
NSLog(@"%@",str);
//把字符串再转变为二进制流
self.receiveData=[NSMutableData dataWithData:[str dataUsingEncoding:NSUTF8StringEncoding]];
//request转变为URL
NSURL *url=[request URL];
//URL转变为nsstring
NSString *str=[[url absoluteString] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSLog(@"%@",str);
NSURL *url=[NSURL URLWithString:@"http://img3.xooimage.com/files/6/1/3/firefox-logo-200x200-19f78a.png"];
//网站转变为二进制流
NSMutableData *data=[NSMutableData dataWithContentsOfURL:url];
UIImage *image=[UIImage imageWithData:data];
//读取文件
NSString *filePath = [[NSBundle mainBundle] pathForResource:@"Students" ofType:@"xml"];
//文件转变为二进制流
NSData *data = [NSData dataWithContentsOfFile:filePath];
//取出首字母
NSString *name = [city objectForKey:@"name"];
NSString *firstStr=[name substringWithRange:NSMakeRange(0, 1)];
//从一个字符串中直接取出数组
NSString *str = [NSString stringWithFormat:@"Norman,Stanley,Fletcher"];
NSArray *arr = [str componentsSeparatedByString:@","];
NSLog(@"arr = %@",arr);
//转码
urlStr = [urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
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