通过字符串化JSON数组属性中包含的值过滤图层 [英] Filter a Layer By a Value Contained in a Stringified JSON Array Property

问题描述

我们的一个Mapbox图块集中的一个表具有ID的字符串化JSON数组属性:

One of the tables in one of our Mapbox tilesets has a stringified JSON array property of ids:

"string_ids":"[\"a\",\"b\"]"

我想使用此属性过滤功能，但似乎无法在

I would like to filter features using this property, but can't seem to find a way to do it in the Predicates and Expressions documentation. So, for instance, I'd like to filter features so only those that have a "string_id" of "a" display.

我相信，这将有助于解决我的问题(准备就绪( https://github.com/mapbox/mapbox-gl-js/issues/4113 )，但是只是想知道此时是否还有其他解决方案?

I believe this will help with my problem, when ready (https://github.com/mapbox/mapbox-gl-js/issues/4113), but just wondering if there's another solution in place at this time?

更新

我尝试了几种不同的方法:

I've tried several different approaches:

• NSPredicate(format: "'a' IN CAST(string_ids, 'NSArray<NSString>')")出现以下错误:尚未将表达式投射到NSArray."
• NSPredicate(format: "string_ids contains[c] %@", "a")不会出错，但没有与过滤器匹配的功能.
• NSPredicate(format: "string_ids LIKE 'a'")出现以下错误:不支持NSPredicateOperatorType:7."

• NSPredicate(format: "'a' IN CAST(string_ids, 'NSArray<NSString>')") errors out with: "Casting expression to NSArray not yet implemented."
• NSPredicate(format: "string_ids contains[c] %@", "a") does not error out, but no features match the filter.
• NSPredicate(format: "string_ids LIKE 'a'")errors out with: "NSPredicateOperatorType:7 is not supported."

推荐答案

截至因此，为了结束我最初的问题的循环，该谓词现在可以按需工作:NSPredicate(format: "string_ids contains 'a'").

So, to close the loop on my original question, this predicate is now working as desired: NSPredicate(format: "string_ids contains 'a'").

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