英文:
How to assign multiple values from a map in a loop in Groovy
问题
在Groovy中，您可以使用each循环来处理这个地图，并且可以通过key和value来访问地图的内容。以下是修改后的代码示例：
def routemap = [ One: ['Berlin','Hamburg'], Two: ['London','Paris'], Three: ['Rome','Barcelona']]
routemap.each { route, startend ->
println "Route: $route"
println "Start: ${startend[0]} End: ${startend[1]}"
}
这个代码会输出您期望的结果：
Route: One
Start: Berlin End: Hamburg
Route: Two
Start: London End: Paris
Route: Three
Start: Rome End: Barcelona
这样就可以正确地访问每个地图项的值了。如果您有任何其他问题，请随时提问。
英文:
I have a map in groovy where each item has multiple values that I need to use in a loop. The number of values is fixed, so could be stored in a list/array, tuple - does not matter.
Example, I tried:
def routemap = [ One: ['Berlin','Hamburg'], Two: ['London','Paris'], Three: ['Rome','Barcelona']]
routemap.each { route, startend ->
println "Route: $route"
println "Start: $startend[0] End: $startend[1]"
}
This does not provide the desired result, the list index does not work.
Route: One
Start: [Berlin, Hamburg][0] End: [Berlin, Hamburg][1]
Route: Two
Start: [London, Paris][0] End: [London, Paris][1]
Route: Three
Start: [Rome, Barcelona][0] End: [Rome, Barcelona][1]
Also I am wondering if there is a better, more elegant way to do it? Is there a way to assign two values (or a pair or tuple like in Python) instead of "startend" in the loop?
答案1
得分: 1
你应该将 $startend[index] 放在大括号内，就像 ${startend[0]} 一样。所以你的代码会看起来像这样：
def routemap = [ One: ['Berlin','Hamburg'], Two: ['London','Paris'], Three: ['Rome','Barcelona']]
routemap.each { route, startend ->
println "Route: $route"
println "Start: ${startend[0]} End: ${startend[1]}" // 这里是修改的部分
}
英文:
You should put $startend[index] in the curly brackets, like ${startend[0]}. So your code will look like that:
def routemap = [ One: ['Berlin','Hamburg'], Two: ['London','Paris'], Three: ['Rome','Barcelona']]
routemap.each { route, startend ->
println "Route: $route"
println "Start: ${startend[0]} End: ${startend[1]}" // here is the change
}
答案2
得分: 1
你可以在startend参数上使用多重赋值：
def routemap = [ One: ['柏林', '汉堡'], Two: ['伦敦', '巴黎'], Three: ['罗马', '巴塞罗那']]
routemap.each{ route, startend ->
def (start, end) = startend
println "路线: $route"
println "起点: $start 终点: $end"
}
输出：
路线: One
起点: 柏林 终点: 汉堡
路线: Two
起点: 伦敦 终点: 巴黎
路线: Three
起点: 罗马 终点: 巴塞罗那
英文:
You can literally use the multiple assignment for the startend argument:
def routemap = [ One: ['Berlin','Hamburg'], Two: ['London','Paris'], Three: ['Rome','Barcelona']]
routemap.each{ route, startend ->
def ( start, end ) = startend
println "Route: $route"
println "Start: $start End: $end"
}
prints
Route: One
Start: Berlin End: Hamburg
Route: Two
Start: London End: Paris
Route: Three
Start: Rome End: Barcelona
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