//====================NSStirng 的常见用法====================

-(void)testString

{

//创建格式化字符串:占位符（由一个%加一个字符组成）

NSString* str1 = [NSString stringWithFormat:@"the first string!"];

NSLog(@"one:::%@",str1);

NSString* str2 = [[NSString alloc]initWithString:@"the second string!"];

NSLog(@"two:::%@",str2);

//从文件中读取字符串

NSString* path = [[NSBundle mainBundle]pathForResource:@"strings" ofType:@"txt"];

//    NSDictionary* contents = [[NSDictionary alloc]initWithContentsOfFile:path];

//    NSArray* keys = [contents allKeys];

NSString* asstring = [[NSString alloc]initWithContentsOfFile:path];

NSLog(@"three:::%@",asstring);

//比较两个字符串

NSString* str3 = @"This is a String!";

NSString* str4 = @"This is a String! tyutuy";

BOOL result = [str3 isEqualToString:str4];

NSLog(@"the result is %d",result);

//输出大小写字母

NSLog(@"upper 大写字母：%@",[str3 uppercaseString]);//大写

//调用appendFormat追加字符串

NSMutableString* muString = [[NSMutableString alloc]initWithString:@"this is a string!"];

[muString appendFormat:@"ending is end!"];

NSLog(@"the result is %@",muString);

//调用appendString方法追加字符串

[muString appendString:@"good life is coming!"];

NSLog(@"%@",muString);

//在指定位置插入字符串

[muString insertString:@"iiiiiii  " atIndex:0];

NSLog(@"%@",muString);

[muString setString:@"sajfk;sadjflsajfkls"];

NSLog(@"%@",muString);

//用指定字符串替换字符串中某指定位置、长度的字符串

[muString replaceCharactersInRange:NSMakeRange(0, 2) withString:@"==="];

NSLog(@"%@",muString);

//文件扩展名

NSString* pathString = @"~/记录.txt";

NSLog(@"Extension:%@",[pathString pathExtension]);

}

//====================NSStirng 的常见用法====================