if-statement

问题 The code checks if the user taps a ball with the same texture as a ball that randomly changes textures. But in my console "Point" is only printed occasionally although I tap on the ball with the same texture as the ball that randomly changes texture. How can this be fixed. Has this something to do with adding a physicsBody to the other balls? override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) { var array = [blueTexture, redTexture, greenTexture, yellowTexture]// var

问题 The code checks if the user taps a ball with the same texture as a ball that randomly changes textures. But in my console "Point" is only printed occasionally although I tap on the ball with the same texture as the ball that randomly changes texture. How can this be fixed. Has this something to do with adding a physicsBody to the other balls? override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) { var array = [blueTexture, redTexture, greenTexture, yellowTexture]// var

问题 Here goes: I want to add text to a file if it exists. The text is to go on each line of the file at the very end. The text to be added is "Note: certain conditions apply" I found syntax to check if the file exists, and syntax for a for loop to add text at the end of the line, but they do not seem to work at the same time in the bat file. Also, advice varies about variable names, using "%" and using the quote marks themselves, so here is what I have (assume everything takes place in the same

问题 Consider this code (written in C to demonstrate the problem): int foo1(int a) { if(a) return 33; return 22; } int foo2(int a) { if(a) return 33; else return 22; } As you can see, foo1(int a) does exactly the same as foo2(int a) . foo1(int a) is shorter, however I get the impression that foo2(int a) is just more logical (that's only my impression). Which one is better? Is it good to use else with if that is the last control statement in function code and its block always executes return ? 回答1:

问题 What I currently have is this: if ((string)Session["PlanID"] == null) { string PlanID = Request.QueryString["PlanID"]; Session["PlanID"] = PlanID; } What I need is something like this: if ((string)Session["PlanID"] == null) or if ((string)Session["PlanID"] == "") { string PlanID = Request.QueryString["PlanID"]; Session["PlanID"] = PlanID; } How would I do that? 回答1: You can use IsNullOrEmpty from string. if (string.IsNullOrEmpty((string)Session["PlanID"])) { string PlanID = Request

问题 What I currently have is this: if ((string)Session["PlanID"] == null) { string PlanID = Request.QueryString["PlanID"]; Session["PlanID"] = PlanID; } What I need is something like this: if ((string)Session["PlanID"] == null) or if ((string)Session["PlanID"] == "") { string PlanID = Request.QueryString["PlanID"]; Session["PlanID"] = PlanID; } How would I do that? 回答1: You can use IsNullOrEmpty from string. if (string.IsNullOrEmpty((string)Session["PlanID"])) { string PlanID = Request

问题 I am attempting to create a search program in shell as an exercise, but when I try to handle empty lines with an if-statement I get a message saying that the shell encountered an unexpected operator. #!/bin/sh file=$1 token=$2 while read line do if [ ! -z $line ] then set $line if [ $1 = $token ] then echo $line fi fi done < $file When I run the program using match_token animals_blanks dog I get ./match_token: 8: [: cat: unexpected operator ./match_token: 8: [: dog: unexpected operator .

问题 I am trying to compare columns in two files to see if the values match, and if there is a match I want to merge/concatenate the data for that row together. My issue is that when reading line by line from the two files separately, I can't get python to iterate through the files together and look for a match. Instead it will iterate properly through one file and iterate over the same line in the second file multiple times... I have had this issue in the past and still not really found a way

问题 Will this fail or better way of scripting/coding the following? (particularly focusing on the first part of the script) Should I be using ELSE statements etc.? Any recommendations would be greatly appreciated! echo Setting Static IP Information... IF %POSID%==11 set IP_Addr=10.102.%DROPZERO%.105 IF %POSID%==12 set IP_Addr=10.102.%DROPZERO%.106 IF %POSID%==13 set IP_Addr=10.102.%DROPZERO%.107 IF %POSID%==14 set IP_Addr=10.102.%DROPZERO%.108 IF %POSID%==15 set IP_Addr=10.102.%DROPZERO%.109 IF

问题 well... can you tell me why this works: {if !$conta|contains:"word1" && ($product->id_category_default < 388 || $product->id_category_default > 475)} and this not: {if (!$conta|contains:"word1" || !$conta|contains:"word2") && ($product->id_category_default < 388 || $product->id_category_default > 475)} where is the syntax error? 回答1: Try this instead: {if !($conta|contains:"word1" || $conta|contains:"word2") && ($product->id_category_default < 388 || $product->id_category_default > 475)} 来源：