default-value

问题 is there \"elegant\" way to give specific property a default value ? Maybe by DataAnnotations, something like : [DefaultValue(\"true\")] public bool Active { get; set; } Thank you. 回答1: You can do it by manually edit code first migration: public override void Up() { AddColumn("dbo.Events", "Active", c => c.Boolean(nullable: false, defaultValue: true)); } 回答2: It's been a while, but leaving a note for others. I achieved what is needed with an attribute and I decorated my model class fields

问题 I\'ve read the examples in python docs, but still can\'t figure out what this method means. Can somebody help? Here are two examples from the python docs >>> from collections import defaultdict >>> s = \'mississippi\' >>> d = defaultdict(int) >>> for k in s: ... d[k] += 1 ... >>> d.items() [(\'i\', 4), (\'p\', 2), (\'s\', 4), (\'m\', 1)] and >>> s = [(\'yellow\', 1), (\'blue\', 2), (\'yellow\', 3), (\'blue\', 4), (\'red\', 1)] >>> d = defaultdict(list) >>> for k, v in s: ... d[k].append(v) ..