map

Delete selected keys from Dart Map

由 柔情痞子 提交于 2020-02-29 11:36:45
问题 What is the Dart idiomatic way to remove selected keys from a Map? Below I'm using a temporary emptyList to hold String keys. Is there a cleaner way? List<String> emptyList = new List<String>(); _objTable.keys.forEach((String name) { if (_objTable[name].indices.isEmpty) { emptyList.add(name); print("OBJ: deleting empty object=$name loaded from url=$url"); } }); emptyList.forEach((String name) => _objTable.remove(name)); 回答1: You can do something like this : _objTable.keys .where((k) =>

Delete selected keys from Dart Map

由 时光怂恿深爱的人放手 提交于 2020-02-29 11:35:50
问题 What is the Dart idiomatic way to remove selected keys from a Map? Below I'm using a temporary emptyList to hold String keys. Is there a cleaner way? List<String> emptyList = new List<String>(); _objTable.keys.forEach((String name) { if (_objTable[name].indices.isEmpty) { emptyList.add(name); print("OBJ: deleting empty object=$name loaded from url=$url"); } }); emptyList.forEach((String name) => _objTable.remove(name)); 回答1: You can do something like this : _objTable.keys .where((k) =>

Delete selected keys from Dart Map

由 不羁岁月 提交于 2020-02-29 11:35:27
问题 What is the Dart idiomatic way to remove selected keys from a Map? Below I'm using a temporary emptyList to hold String keys. Is there a cleaner way? List<String> emptyList = new List<String>(); _objTable.keys.forEach((String name) { if (_objTable[name].indices.isEmpty) { emptyList.add(name); print("OBJ: deleting empty object=$name loaded from url=$url"); } }); emptyList.forEach((String name) => _objTable.remove(name)); 回答1: You can do something like this : _objTable.keys .where((k) =>

SenchaTouch2.1调用百度地图实例

由 ℡╲_俬逩灬. 提交于 2020-02-29 05:34:47
SenchaTouch（以下简称st）里面使用的地图示例是采用的googleMap，但由于和谐社会的原因，google地图对我们的支持也是有心无力。在st的使用中也是经常出现无法加载googlemap的js。 但是没了谷歌地图我们依然还是要做开发。不能因为了它就不用地图了不是。下面介绍国内的地图：百度地图。读者可能有些疑惑，因为参考的api使用的都是谷歌的，如果换成百度一下子变得无从下手。故往下看文章的朋友请注意了几点 1、抛开st提供的map组件（xtype:map），在文中的调用百度地图不需要在使用到这个组件了。 2、抛开st中的map示例所提到的步骤，因为在调用百度地图的过程中并没有那么复杂。 3、闲话不多说，进入正题。 调用步骤： 1、创建st项目，详情参考另外一篇文章《Secnha Commands 3 使用详解（从创建到打包》 http://my.oschina.net/victorHomePage/blog/109654 ，项目的创建方式有很多，本文就采用命令方式。 2、打开index.html文件，加入以下代码。 <!--添加下面的meta标签： --> <meta name="viewport" content="initial-scale=1.0, user-scalable=no" /> <!--这样做是为了让页面以正常比例进行显示并且禁止用户缩放页面的操作。

STL Map with a Vector for the Key

由 爷，独闯天下 提交于 2020-02-26 08:03:37
问题 I'm working with some binary data that I have stored in arbitrarily long arrays of unsigned ints. I've found that I have some duplication of data, and am looking to ignore duplicates in the short term and remove whatever bug is causing them in the long term. I'm looking at inserting each dataset into a map before storing it, but only if it was not found in the map to start with. My initial thought was to have a map of strings and use memcpy as a hammer to force the ints into a character array

STL Map with a Vector for the Key

由 你说的曾经没有我的故事 提交于 2020-02-26 08:03:31
问题 I'm working with some binary data that I have stored in arbitrarily long arrays of unsigned ints. I've found that I have some duplication of data, and am looking to ignore duplicates in the short term and remove whatever bug is causing them in the long term. I'm looking at inserting each dataset into a map before storing it, but only if it was not found in the map to start with. My initial thought was to have a map of strings and use memcpy as a hammer to force the ints into a character array

c++ pass a map by reference into function

由 旧巷老猫 提交于 2020-02-18 08:22:11
问题 How can I pass a map by reference into a function? Visual Studio 2010 is giving me an unresolved externals error. Currently, I have the following simplified code: void function1(){ map<int, int> * my_map = new map<int, int>(); function2(*my_map); } void function2(map<int, int> &temp_map){ //do stuff with the map } There's a few answers to similar questions here, but they make use of typedef and adding std:: to the beginning of the definition but I'm really not sure why. int ComputerPlayer:

c++ pass a map by reference into function

由 北慕城南 提交于 2020-02-18 08:20:47
问题 How can I pass a map by reference into a function? Visual Studio 2010 is giving me an unresolved externals error. Currently, I have the following simplified code: void function1(){ map<int, int> * my_map = new map<int, int>(); function2(*my_map); } void function2(map<int, int> &temp_map){ //do stuff with the map } There's a few answers to similar questions here, but they make use of typedef and adding std:: to the beginning of the definition but I'm really not sure why. int ComputerPlayer:

Restrict the viewable part of a tile to a polygon area in Leaflet?

由 冷暖自知 提交于 2020-02-05 03:49:14
问题 In Leaflet, how does one restrict the viewable part of a tile to the area contained within a polygon (or geojson), i.e., the intersection between a polygon and the tile beneath. Example use : display only one country and hide all others. EDIT: I'm not looking for the fitBounds/setMaxBounds method but for a way to display only the inner area of a polygon. 回答1: You can use the map.setMaxBounds(L.latLngBounds) method to restrict the view. For restricting the map view: map.fitBounds(polygon

making a map in which the value type is an abstract class in C++

由 丶灬走出姿态 提交于 2020-02-03 18:15:43
问题 I have an abstract class element and a child class elasticFrame : class element { public: virtual Matrix getStiffness() = 0; protected: Matrix K; }; class elasticFrame3d:public element { public: elasticFrame3d(double E, double G); virtual Matrix getStiffness(); virtual Matrix getTransform(); private: double E, G; }; what I want is to make a map like this: map<int, element> elementMap; but when I get this error: error C2259: 'element' : cannot instantiate abstract class is it even possible to
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