1.字典或者数组转化为NSString
NSArray*arr= [NSArrayarrayWithObject:@"1"];
NSString*str= [arrJSONString];//数组或者字典转化为json串
NSArray*arr1= [strobjectFromJSONString];//json串转化为字典或者数组
NSData*data= [arr1JSONData];//把json串转化为Nsdata
NSString*str1= [[NSStringalloc]initWithData:dataencoding:NSUTF8StringEncoding];
//把NSdata转为为NSString
NSData*data1= [str1dataUsingEncoding:NSUTF8StringEncoding];//把NSString转化为NSData
2.二进制流转变为字符串
NSString*str=[[NSMutableStringalloc]initWithData:self.receiveDataencoding:NSUTF8StringEncoding];
//转变其中的内容
str=[strstringByReplacingOccurrencesOfString:@","withString:@",\n"];
str=[strstringByReplacingOccurrencesOfString:@"{"withString:@"{\n"];
str=[strstringByReplacingOccurrencesOfString:@"}"withString:@"\n}"];
NSLog(@"%@",str);
//把字符串再转变为二进制流
self.receiveData=[NSMutableDatadataWithData:[strdataUsingEncoding:NSUTF8StringEncoding]];
3.request转变为URL
NSURL*url=[requestURL];
//URL转变为nsstring
NSString*str=[[urlabsoluteString]stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSLog(@"%@",str);
4.网站转变为二进制流
NSMutableData*data=[NSMutableDatadataWithContentsOfURL:url];
UIImage*image=[UIImageimageWithData:data];
4.读取文件
NSString*filePath
= [[NSBundlemainBundle]pathForResource:@"Students"ofType:@"xml"];
5.文件转变为二进制流
NSData*data
= [NSDatadataWithContentsOfFile:filePath];
//取出首字母
NSString*name
= [cityobjectForKey:@"name"];
NSString*firstStr=[namesubstringWithRange:NSMakeRange(0,1)];
6.从一个字符串中直接取出数组
NSString*str
= [NSStringstringWithFormat:@"Norman,Stanley,Fletcher"];
NSArray*arr
=
[strcomponentsSeparatedByString:@","];
NSLog(@"arr= %@",arr);
6.转码
urlStr=[urlStrstringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];