numbers

Can someone help my pea brain figure out why my simple regular expression is not working as I am expecting/wanting it to. I want to match a date format of MM/DD/YYYY with exactly 2 and 4 digits, so something like 01/16/1955. My code below does that, but it also matches 2+ and 4+ digits, so something like 011/16/1955 or 01/16/19555 (1 extra digit) pass my validation as well. //validate date of birth var dob_label = $date_of_birth.find('label').text().slice(0, -1), dob_mm = $dob_mm.val(), dob_dd = $dob_dd.val(), dob_yyyy = $dob_yyyy.val(), regex_two_digit = /^\d{2}$/, regex_four_digit = /^\d{4}$

After a very thorough read of the Python's decimal module documentation , I still find myself puzzled by what happens when I divide a decimal. In Python 2.4.6 (makes sense): >>> import decimal >>> decimal.Decimal(1000) / 10 Decimal("100") In Python 2.5.6, Python 2.6.7, and Python 2.7.2 (puzzling): >>> import decimal >>> decimal.Decimal(1000) / 10 Decimal('0.00000-6930898827444486144') More confusing yet, that result doesn't even appear to be valid: >>> decimal.Decimal('0.00000-6930898827444486144') Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/opt/local/Library

什么是Stream？ 　　Stream（流）是一个来自数据源的元素队列并且支持聚合操作，元素流在管道中经过中间操作，最终操作得到结果。 　　 数据源 ：集合，数组，I/O channel,产生器generator。 　　 聚合操作 ：类似于sql比如：filter，find,map,match,sorted. 生成流: stream() − 为集合创建串行流。 parallelStream() − 为集合创建并行流。 通过例子看方法： list.stream().limit(10).sorted().forEach(System.out::println); 上面例子：取前10条》排序》循环输出 List<Integer> numbers = Arrays.asList(3, 2, 2, 3, 7, 3, 5);List<Integer> squaresList = numbers.stream().map( i -> i*i).distinct().collect(Collectors.toList()); 上面例子：将本身映射成本身的平方》去重》转化为list 　 List<String>strings = Arrays.asList("abc", "", "bc", "efg", "abcd","", "jkl");String mergedString = strings

This code in my form updates the textBox1.Text twice whenever number keys are pressed. private void textBox1_KeyDown( object sender, KeyEventArgs e ) { //MessageBox.Show(); if( char.IsNumber((char)e.KeyCode) ) { textBox1.Text += (char)e.KeyCode; } } Explain why if you can? Modify the code or provide me a better solution for this. Input ( in textbox1 ): 54321 Output: 1234554321 When you press a key, a character is already appended to your TextBox . Then you run the following code and, if the key represents a number, you append it again: if (char.IsNumber((char)e.KeyCode)) { textBox1.Text +=