如何处理Firestore查询结果以供以后使用

huangapple
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英文:

How to handle Firestore Query Results for later usage

问题

I am currently struggling with my Firestore query results.
What I want to do is to query the database, fetch the results, write the result in an array --> this is already working with my code below!
But in addition to this I need that array later to compare it to a different array from a second query and this is where the issue is.

  1. var arrayOfTuples = [(Int, String)]()
  2.        
  3. db.collection("Data").whereField("age", isGreaterThanOrEqualTo: 1).whereField("age", isLessThanOrEqualTo: 50).whereField("gender", isEqualTo: "F").getDocuments() { (querySnapshot, err) in
  4.     if let err = err {
  5.         print("Error getting documents: \(err)")
  6.     } else {
  7.              for (index, document) in querySnapshot!.documents.enumerated() {
  8.              arrayOfTuples += [(index, document.documentID)]
  9.              }       
  10.     }
  11.     // Place where I need the array result
  12. }
  13. // Continue with your code here

I can use the array result in the last print method, but I need it out of the last bracket that I can compare it to the second query result.
Have not found anything that I could return the result, but maybe it's completely simple (hope so).

Hope it's clear, otherwise just let me know.
Thanks!

英文:

I am currently struggling with my Firestore query results.
What I want to do is to query the database, fetch the results, write the result in an array --> this is already working with my code below!
But in addition to this I need that array later to compare it to a different array from a second query and this is where the issue is.

  1. var arrayOfTuples = [(Int, String)]()
  2.        
  3. db.collection("Data").whereField("age", isGreaterThanOrEqualTo: 1).whereField("age", isLessThanOrEqualTo: 50).whereField("gender", isEqualTo: "F").getDocuments() { (querySnapshot, err) in
  4.     if let err = err {
  5.         print("Error getting documents: \(err)")
  6.     } else {
  7.              for (index, document) in querySnapshot!.documents.enumerated() {
  8.              arrayOfTuples += [(index, document.documentID)]
  9.              }       
  10.     }
  11.     print(arrayOfTuples)
  12. } 
  13. //Place where I need the array result

I can use the array result in the last print method, but I need it out of the last bracket that I can compare it to the second query result.
Have not found anything that I could return the result, but maybe it's completely simple (hope so).

Hope it's clear, otherwise just let me know.
Thanks!

答案1

得分: 2

你无法将异步调用变成同步，你需要

  1. func loadQuery(com: @escaping ([(Int, String)] -> ())) {
  2.     var arrayOfTuples = [(Int, String)]()
  3.     db.collection("Data")
  4.         .whereField("age", isGreaterThanOrEqualTo: 1)
  5.         .whereField("age", isLessThanOrEqualTo: 50)
  6.         .whereField("gender", isEqualTo: "F")
  7.         .getDocuments() { (querySnapshot, err) in
  8.             if let err = err {
  9.                 print("Error getting documents: \(err)")
  10.             } else {
  11.                 for (index, document) in querySnapshot!.documents.enumerated() {
  12.                     arrayOfTuples += [(index, document.documentID)]
  13.                 }
  14.             }
  15.             com(arrayOfTuples)
  16.         }
  17. }
  19. loadQuery { arr in
  20.     // 在这里进行比较
  21. }
英文:

You can't make an asynchronous call synchronous you need

  1. func loadQuery(com:@escaping( [(Int, String)] -> ())){ 
  2.     var arrayOfTuples = [(Int, String)]() 
  3. 	db.collection("Data").whereField("age", isGreaterThanOrEqualTo: 1).whereField("age", isLessThanOrEqualTo: 50).whereField("gender", isEqualTo: "F").getDocuments() { (querySnapshot, err) in
  4. 		if let err = err {
  5. 			print("Error getting documents: \(err)")
  6. 		} else {
  7. 				 for (index, document) in querySnapshot!.documents.enumerated() {
  8. 				 arrayOfTuples += [(index, document.documentID)]
  9. 				 }       
  10. 		}
  11. 		com(arrayOfTuples)
  12. 	} 
  13. }
  1. loadQuery { arr in 
  2.   // compare here 
  3. }

huangapple
  • 本文由 发表于 2020年1月3日 23:32:01
  • 转载请务必保留本文链接：https://go.coder-hub.com/59581234.html
  • arrays
  • google-cloud-firestore
  • ios
  • swift

在Nunjucks模板中访问数组在 :?: :razz: :sad: :evil: :!: :smile: :oops: :grin: :eek: :shock: :???: :cool: :lol: :mad: :twisted: :roll: :wink: :idea: :arrow: :neutral: :cry: :mrgreen:

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