tostring

Recently I have had to serialize a double into text, and then get it back. The value seems to not be equivalent: double d1 = 0.84551240822557006; string s = d1.ToString("R"); double d2 = double.Parse(s); bool s1 = d1 == d2; // -> s1 is False But according to MSDN: Standard Numeric Format Strings , the "R" option is supposed to guarantee round-trip safety. The round-trip ("R") format specifier is used to ensure that a numeric value that is converted to a string will be parsed back into the same numeric value Why did this happen? Mehrdad I found the bug. .NET does the following in clr\src\vm

This question already has an answer here: How do I print my Java object without getting “SomeType@2f92e0f4”? 10 answers I have an ArrayList that contains some objects from User class. When I print these objects I got: [User@18fd984, User@18fd984] How to print these objects in a correct way? Override the method toString in the class to produce the output you prefer, instead of the default value that Java automatically generates. Example: public class User { private String name; ... @Override public String toString() { return name; } } For complex objects, Apache Commons Lang provides some handy

This question already has an answer here: Convert String to int array in java 9 answers Is there in the JDK or Jakarta Commons (or anywhere else) a method that can parse the output of Arrays.toString, at least for integer arrays? int[] i = fromString(Arrays.toString(new int[] { 1, 2, 3} ); Sam Pretty easy to just do it yourself: public class Test { public static void main(String args[]){ int[] i = fromString(Arrays.toString(new int[] { 1, 2, 3} )); } private static int[] fromString(String string) { String[] strings = string.replace("[", "").replace("]", "").split(", "); int result[] = new int

This question already has an answer here: Double to string conversion without scientific notation 17 answers I just came across the wonderful "feature" that .NET will by default do Double.ToString() using scientific notation if there are enough decimal places. .005.ToString() // ".005" .00005.ToString() // "5E-05" Does anyone know an efficient way to get this to appear as a string in standard (non-scientific) notation? I've seen this question , but the top two answers seem kind of hacky to me as they both do Double.ToString() and then just reformat the results. Thanks for any help. EDIT: The

1 属性的删除：delete 命令 delete 命令用于删除对象的属性，删除成功后返回 true 。 var obj = { p: 1 }; Object.keys(obj) // ["p"] delete obj.p // true obj.p // undefined Object.keys(obj) // [] 　　 上面代码中， delete 命令删除对象 obj 的 p 属性。删除后，再读取 p 属性就会返回 undefined ， 　　而且 Object.keys 方法的返回值也不再包括该属性。 　　 注意，删除一个不存在的属性， delete 不报错，而且返回 true 。 var obj = {}; delete obj.p // true 　　 上面代码中，对象 obj 并没有 p 属性，但是 delete 命令照样返回 true 。 　　因此，不能根据 delete 命令的结果，认定某个属性是存在的。 　　只有一种情况， delete 命令会返回 false ，那就是该属性存在，且不得删除 var obj = Object.defineProperty({}, 'p', { value: 123, configurable: false }); obj.p // 123 delete obj.p // false 　　 上面代码之中，对象 obj 的 p