【学习笔记】【Foundation】字符串

NSString

创建字符串：

char *str="string"

NSString* str=@“创建字符串”；

NSString* str=[[NSString alloc]initWithString:@"string"];

NSString* str=[[NSString alloc]initWithFormat:@"age is %d",5];

NSString* str=[[NSString alloc]initWithUTF8String:"abc"];

NSString* str=[[NSString alloc]stringWithString:@"string"];

NSString *str=[NSStringFromRange(range)];

//将数据转化为字符串

NSString* str=[array compenentsJoinedByString:@","];

获取字符串长度

[str length];

获取字符串中的字符或字节：

NSString* s1=[str substringToIndex:10];

NSString* s2=[str substringFromIndex:5];

NSString* s3=[str substringWithRange:NSMakeRange(5,10)];

char c=[str characterAtIndex:1];

获取字符串对应的c风格字符串

const char* cstr=[str UTF8String];

连接字符串：

str=[str stringByAppendingString:@"ios"];

str=[str stringByAppengdingFormat:@"%@is a good book",book]; NSString* book=@"hahaha";

查找字符串内指定的字符或子串：

NSRange pos=[str rangeOfString:@"ios"]; //搜索到就停止搜索，如果需要继续搜索或者从后面搜索可以设置第二个参数;

对字符串进行大小写转换：

str=[str uppercaseString];  //大写

str=[str lowercaseString];  //小写

str=[str capitalizedString]; //首字母大写

比较字符串：

[str isEqualToString: @"ios"];

分割字符串：

NSArray* array=[str componentSeperatedByString:@"."];

类型转换：

NSLog(@“%i”, [@"10" intValue]);

字符串大小比较：

[str compare:s1];

NSMutableString

创建字符串:

NSMutableString* str=[[NSMutableString alloc]initWithCapacity:10];

[str setString:@"sb ni hao"];

追加字符串：

[str appendString:@"hahaha"];

[str appendFormat:@"%i is my age,21"];

替换字符串：

[str replaceCharacterInRange:range withString:@"yoyoyo~"];

NSRange range=[str rangeOfString:@"age"];

删除字符串

[str deleteCharacterInRange:NSMakeRange(location,length)];

插入字符串

[str insertString:@"ni ge sb" atIndex:6];