Object-c字符串操作

字符串操作：

-(void) testString{

    NSString *str1 = @"some string";

    NSLog(@"%@", str1);

    //格式化字符串

    NSString *str2 = [NSString stringWithFormat:@"%@ %@", @"hello", @];

    NSLog(@"%@", str2);

    //获取以数字开头的字符串的数字

    NSString *str3 = @“.3abc12";

    double temp1 = [str3 floatValue];

    NSInteger temp2 = [str3 integerValue];

    NSLog(@"%f", temp1);

    NSLog(@"%lu", temp2);

    //获取字符串长度

    NSUInteger len = [str3 length];

    NSLog(@"%lu", len);

    //比较字符串

    NSString *str4 = @“.3abC12";

    BOOL isEqual = [str3 isEqualToString:str4];

    NSLog(@"%hhd", isEqual);

    //比较字符串（不区分大小写）

    isEqual = ([str3 caseInsensitiveCompare:str4] == NSOrderedSame);

    NSLog(@"%ld", (long)[str3 caseInsensitiveCompare:str4]);

    NSLog(@"%hhd", isEqual);

    //将字符串全部字符转换为大写字符

    str4 = [str4 uppercaseString];

    NSLog(@"%@", str4);

    //将字符串全部字符转换为小写字符

    str4 = [str4 lowercaseString];

    NSLog(@"%@", str4);

    //去除字符串空字符

    NSString *str5 = @"   one two three   ";

    //去除字符串空字符，包括前后空格，换行符

    str1 = [str5 stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

    //去除字符串空字符，包括前后空格

    str2 = [str5 stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];

    NSLog(@"%@",str1);

    NSLog(@"%@",str2);

    //获得substring

    str3 = [str1 substringToIndex:];

    str4 = [NSString stringWithFormat:@"%@%@",[str2 substringFromIndex:], @"" ];

    NSLog(@"%@", str3);

    NSLog(@"%@", str4);

    //分割字符串

    NSArray *arr = [str1 componentsSeparatedByString:@" "];

    NSLog(@"%@", arr);

}

对应输出结果：

-- ::02.607 test2[:] some string

-- ::02.607 test2[:] hello

-- ::02.608 test2[:] 124.300003

-- ::02.608 test2[:]

-- ::02.608 test2[:]

-- ::02.608 test2[:]

-- ::02.608 test2[:]

-- ::02.608 test2[:]

-- ::02.608 test2[:] .3ABC12

-- ::02.608 test2[:] .3abc12

-- ::02.608 test2[:] one two three

-- ::02.608 test2[:] one two three

-- ::02.608 test2[:] one

-- ::02.608 test2[:] two three111

-- ::02.608 test2[:] (

    one,

    two,

    three

)