variables

问题 I'm trying to receive some data being sent to a webhook and work with it. I'm able to receive the data and convert it to a json String however I want to assign the json String to a global variable so I can use it elsewhere, and in other functions. I'm declaring the variable first and then trying to assign the json string to it when i receive it but it doesn't seem to be working - the variable is still 'undefined' var jsonData; function doPost(e){ try{ var jsonString = e.postData

问题 I'm trying to receive some data being sent to a webhook and work with it. I'm able to receive the data and convert it to a json String however I want to assign the json String to a global variable so I can use it elsewhere, and in other functions. I'm declaring the variable first and then trying to assign the json string to it when i receive it but it doesn't seem to be working - the variable is still 'undefined' var jsonData; function doPost(e){ try{ var jsonString = e.postData

问题 i have error in my syntax : SET @start := 0; SELECT (ROUND((count(item))/2)) FROM car INTO @until; SELECT * from car limit @until OFFSET @start; You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '@until OFFSET @start' at line 1 anyone can help me? thanks 回答1: You cannot use a user-assigned variable ( @until ) in the LIMIT clause. A possible solution (a variation on this): SELECT (ROUND((count(item))/2)) FROM

问题 i have error in my syntax : SET @start := 0; SELECT (ROUND((count(item))/2)) FROM car INTO @until; SELECT * from car limit @until OFFSET @start; You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '@until OFFSET @start' at line 1 anyone can help me? thanks 回答1: You cannot use a user-assigned variable ( @until ) in the LIMIT clause. A possible solution (a variation on this): SELECT (ROUND((count(item))/2)) FROM

问题 I am writing a bash program that takes options. For example : ./my_program -l 3 -a -s -l 3 will limit the output to three lines -a will select all my file -s will sort the output For now, I could use two options at a time this way: if [ $all == 1 ] then if [ $sort == 1 ] then printf '%s\n' "${haikus[@]}" | sed -e 's/^[ \t]*//' | sort else printf '%s\n' "${haikus[@]}" | sed -e 's/^[ \t]*//' fi fi If -a option, I print the whole file, or, if -a option and -s option, I use the same command but i

问题 How can I access a variable inside a function which is inside a function in javascript ? var a; var surveyObjects = Parse.Object.extend(surveyObject); var query= new Parse.Query(surveyObjects); query.count({ success: function(count){a = count;}, error: function(error){} }); alert("count of function "+a); a is showing undefined value. I need to use the value of a outside. 回答1: You can do this by using implicit global variable behaviour. function one(){ function two(){ a=10; } two(); } one();

问题 I have a variable t t = 0 I want to start an event whenever t value is changed. How ? There's no valuechanged.connect properties or anything for variables... 回答1: For a global variable, this is not possible using assignment alone. But for an attribute it is quite simple: just use a property (or maybe __getattr__/__setattr__). This effectively turns assignment into a function call, allowing you to add whatever additional behaviour you like: class Foo(QWidget): valueChanged = pyqtSignal(object)

问题 I have a variable t t = 0 I want to start an event whenever t value is changed. How ? There's no valuechanged.connect properties or anything for variables... 回答1: For a global variable, this is not possible using assignment alone. But for an attribute it is quite simple: just use a property (or maybe __getattr__/__setattr__). This effectively turns assignment into a function call, allowing you to add whatever additional behaviour you like: class Foo(QWidget): valueChanged = pyqtSignal(object)

问题 I was using a lambda statement to perform math, and happened to repeatedly use one certain value. Therefore I was wondering if it was possible to assign and use a variable within a lambda statement. I have tried things like: a = lambda n:(b=3+2*n) #[my math here] However this just raises errors, and I was wondering if there was a way to do this. 回答1: Nope, you can't. Only expressions allowed in lambda: lambda_expr ::= "lambda" [parameter_list]: expression lambda_expr_nocond ::= "lambda"

问题 I defined a YAML build-pipeline in azure: variables: test: '${{ variables.Environment }}' pool: vmImage: 'ubuntu-latest' steps: - script: | echo $(test) displayName: 'Show test' I queue that pipeline with the Environment variable defined as 'abc': I expect it to echo abc but instead abc is replaced with nothing - variables.Environment seems to be undefined. Later on I want to load a different Variable Group depending on the Environment variable, which is why I do not echo $(Environment)