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Variable declaration necessary in for loop?

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问题 What is the difference between: for (var i=0; i<5; i++) {} for (i=0; i<5; i++) {} And is it necessary to include the var keyword? I understand that the var keyword affects variable scope, but I'm having trouble understanding if it's necessary to include the keyword in for loops. 回答1: In the second example, your variable is defined globally, so if you're in the browser environment, you can access it from the window object. The first one is an equivalent of: var i; for (i=0; i<5; i++) {} as all

Search Multiple Strings (from File) in a file and print the line

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问题 Again apologies for been noob here: Trying below code for searching multiple strings read from keywords and search in f and printing the line. It works if I have only one keyword but not if I have more then one. keywords = input("Please Enter keywords path as c:/example/ \n :") keys = open((keywords), "r").readline() with open("c:/saad/saad.txt") as f: for line in f: if (keys) in line: print(line) 回答1: One of the challenges of looking for keywords is defining what you mean by keyword and how

Capture search engine keywords in php

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问题 In awstats I get a table with all the key words and phrases used to find my website. I would like to capture this myself however each search engine url is in a different format. When google is the referer I can use the variable q from the querystring as the search term (e.g. google.com?q=my+keywords) however another search engine may have the format searchengine.com?search=my+keywords Is there a generic way of identifying search keywords? Or am I going to have to create a regex/filter for

What effect does the “new” keyword have in C# and why is it only a warning when not employed?

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Consider the following code: public abstract class Test1 { public object Data { get; set; } } public abstract class Test2<T> : Test1 { public T Data { get; set; } } This will generate the following warning: 'Test2.Data' hides inherited member 'Test1.Data'. Use the new keyword if hiding was intended. Why is this only a warning and what effect will adding the "new" keyword have? According to my testing I cannot find any difference once the "new" keyword is added. Don't get me wrong, I'm all for being explicit, but I was curious as to the benefit of adding "new". My only thoughts on what it might

Is it possible to “escape” a method name in PHP, to be able to have a method name that clashes with a reserved keyword?

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问题 I'm doing MVC in PHP, and i'd like to have a list() method inside my Controller, to have the URL /entity/list/parent_id, to show all the "x" that belong to that parent. However, I can't have a method called list(), since it's a PHP reserved keyword. In VB.Net, for example, if I need to have something with a name that clashes with a reserved keyword, I can wrap it in [reserved_name]. In SQL, you can do the same thing. In MySQL, you use the backtick ` Is there some syntax in PHP that specifies

CakePHP Model Name Uses PHP Reserved Word

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问题 Hey I have coded CakePHP for a number of things but never ran into this problem before surprisingly. Also I have thoroughly searched the net and CakePHP docs and have not found an answer to my question. My question is, I have a table for my model that should be named Class, obviously I cannot use that name though since it's a reserved PHP keyword. What options do I have to be able to refer to this model appropriately. So far I have; Renamed my class model file to player_class.php Renamed my

Using “is” keyword with “null” keyword c# 7.0

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问题 Recently i find out, that the following code compiles and works as expected in VS2017. But i can't find any topic/documentation on this. So i'm curious is it legit to use this syntax: class Program { static void Main(string[] args) { var o = new object(); Console.WriteLine(o is null); o = null; Console.WriteLine(o is null); Console.ReadLine(); } } BTW this is not working in VS2015 回答1: Yes, it's entirely valid. This uses the pattern matching feature of C# 7, which is available with is

What is the difference between “keyword” and “reserved word”?

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问题 What's the difference between a keyword and a reserved word ? For example, in the proposal for concepts in C++ one can read the following statement: This proposal introduces five new keywords: concept, concept map, where, axiom, and late check. All of these keywords will also be reserved words. 回答1: Keywords have a special meaning in a language, and are part of the syntax. Reserved words are words that cannot be used as identifiers (variables, functions, etc.), because they are reserved by

Visual Studio default Auto Complete to use System Type Name

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Strange question but my boss is a touch old school and has insisted in our coding standards that we do not use C# shorthands for system types, he likes us to use the full system name. He likes things to be verbose and I happily comply with the standard. However, something which after several months has started to grate on me is the fact that visual studio does not like to comply with the standard when completing code. So if I type: KeyValuePair<Int32, Object> MyValue = new Visual studio will finish the rest with: KeyValuePair<int,object> This is even worse when implementing an interface or

TextBoxFor @Value (uppercase) instead @value

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This is just for curiosity Why does this code work: Html.TextBoxFor(x => x.Age, new { @Value = "0"}) and this doesn't: Html.TextBoxFor(x => x.Age, new { @value = "0"}) Note the uppercase 'V' in @Value I know value is a keyword, but so is readonly and it works. It's not necessary to use @Readonly (with uppercase 'R'). Does anybody have a clue? I'm not 100% sure but, that could be value is a keyword in properties, readonly isn't. Look at properties from MSDN . CodesInChaos InputExtensions.TextBoxFor special cases cases a few attribute names, among them value (case sensitive). This is unrelated