在Groovy中检查字符串列表

Question

I'm new to groovy and have the following code in testing:

groovy> def country_list = [] 
groovy> country_list =['sg', 'ph', 'hk'] 
groovy> for (String item : country_list) { 
groovy>     println item 
groovy>     if (country_list[item].toUpperCase() == "PH") 
groovy>         isPH = true 
groovy> } 
groovy> println isPH 

When run in console, it throws the exception below:

sg
Exception thrown

groovy.lang.MissingPropertyException: Exception evaluating property 'sg' for java.util.ArrayList, Reason: groovy.lang.MissingPropertyException: No such property: sg for class: java.lang.String
at ConsoleScript6.run(ConsoleScript6:5)

What does the error mean ?

I do resolve the issue by this :

isPH = ('PH' in country_list) || ('ph' in country_list)

But really want to understand the error above. Thanks, Paul

Answer 1

That is because, you have list country_list . But using map notation to fetch the value.

sg is the first element in the list of for loop. It was assuming to fetch the property sg from country_list and there is no such property and sg only value on the contrary.

Hence the error which is obivious:

ERROR groovy.lang.MissingPropertyException: Exception evaluating property 'sg' for java.util.ArrayList, Reason: groovy.lang.MissingPropertyException: No such property: sg for class: java.lang.String

You can simple check / assert using below script:

def country_list =['sg', 'ph', 'hk']
def isPH = country_list.find { it.toUpperCase() == 'PH' } ? true : false
assert isPH, 'No ph in the list'
println "Is country list contains ph ? $isPH"

Answer 2

Change country_list[item] to item .

This is because groovy looks property sg for class ArrayList since groovy Object.getAt(String property) method returns the value of property

Answer 3

Yeah the error is not obvious; anyways the country_list[item].toUpperCase() is causing the issue, I guess you want to use item.toUpperCase() instead.

Try this:

def country_list = [] 
 country_list =['sg', 'ph', 'hk'] 
 for (String item : country_list) { 
     println item 
     if (item.toUpperCase() == "PH") 
         isPH = true 
 } 
 println isPH 

Run the solution on groovyConsole here .