for循环创建重复项。 iOS，Swift

时间：2017-08-12 18:32:00

标签： ios arrays dictionary for-loop

我有一个循环，它采用数组元素作为邮政编码，并将它们在for循环中更改为纬度，经度，标题和邮政编码，而不是创建和附加结果数组。在原始数组中有3个邮政编码，它用打印显示这个，但由于某种原因，循环不仅循环3次，它做了很多次，这给了我重复的数据，我已经看了删除重复，这在某种程度上工作，留下3个结果，但有时结果是好的，其中邮政编码和标题都不同，但在某些情况下，它返回与2个不同的邮政编码相同的标题。

任何人都能帮助我指出正确的方向吗？

self.places = self.pCodes

// Loop start
for eachAddress in self.places {
                                let geocoder = CLGeocoder()
                                geocoder.geocodeAddressString(eachAddress) {
                                    placemarks, error in
                                    let placemark = placemarks?.first
                                    let lat = placemark?.location?.coordinate.latitude
                                    let lon = placemark?.location?.coordinate.longitude
                                    let postPcode = eachAddress
                                    let locationTitle = self.cNames[self.lt]
                                    let latLon = ["Post Code": postPcode, "title": locationTitle, "latitude":lat!, "longitude": lon!] as [String : Any]

                                    self.posts.append(latLon)

                                 // adding 1 to lt to pick the next title in the array

                                    if self.lt < (self.pCodes.count - 1) {
                                    self.lt += 1

                                    }else {
                                        self.lt = (self.pCodes.count - 1)
                            }


                                // removing duplicates
                                    var set = Set<String>()
                                    let arraySet: [[String : Any]] = self.posts.flatMap {
                                        guard let name = $0["Post Code"] as? String else {return nil }
                                        return set.insert(name).inserted ? $0 : nil
                                    }


                                    self.postsFinal = arraySet
                                    print("Tony Places \(self.places)")
                                    print("Tony: postsFinal \(self.postsFinal)")
                                    self.showSightingsOnMap()
                        }
                    }

这是我得到的打印件。

  

Tony Places [＆＃34; OL8 2TT＆＃34;，＆＃34; PO1 5DS＆＃34;，＆＃34; PO1 5JA＆＃34;]   Tony：postsFinal [[＆＃34;纬度＆＃34;：53.514649900000002，＆＃34;邮政编码＆＃34;：＆＃34; OL8 2TT＆＃34;，＆＃34;标题＆＃34;：＆＃34; JDFG VBF＆＃34;，＆＃34;经度＆＃34;：-2.1052824000000001]]   Tony Places [＆＃34; OL8 2TT＆＃34;，＆＃34; PO1 5DS＆＃34;，＆＃34; PO1 5JA＆＃34;]   Tony：postsFinal [[＆＃34;纬度＆＃34;：53.514649900000002，＆＃34;邮政编码＆＃34;：＆＃34; OL8 2TT＆＃34;，＆＃34;标题＆＃34;：＆＃34; JDFG VBF＆＃34;，＆＃34;经度＆＃34;：-2.1052824000000001]]   Tony Places [＆＃34; OL8 2TT＆＃34;，＆＃34; PO1 5DS＆＃34;，＆＃34; PO1 5JA＆＃34;]   Tony：postsFinal [[＆＃34;纬度＆＃34;：53.514649900000002，＆＃34;邮政编码＆＃34;：＆＃34; OL8 2TT＆＃34;，＆＃34;标题＆＃34;：＆＃34; JDFG VBF＆＃34;，＆＃34;经度＆＃34;：-2.1052824000000001]]   Tony Places [＆＃34; OL8 2TT＆＃34;，＆＃34; PO1 5DS＆＃34;，＆＃34; PO1 5JA＆＃34;]   Tony：postsFinal [[＆＃34;纬度＆＃34;：53.514649900000002，＆＃34;邮政编码＆＃34;：＆＃34; OL8 2TT＆＃34;，＆＃34;标题＆＃34;：＆＃34; JDFG VBF＆＃34;，＆＃34;经度＆＃34;：-2.1052824000000001]，[＆＃34;纬度＆＃34;：50.800523599999998，＆＃34;邮政编码＆＃34;：＆＃34; PO1 5DS＆＃34;， ＆＃34; title＆＃34;：＆＃34; QWER QWE＆＃34;，＆＃34;经度＆＃34;：-1.0723248000000001]]   Tony Places [＆＃34; OL8 2TT＆＃34;，＆＃34; PO1 5DS＆＃34;，＆＃34; PO1 5JA＆＃34;]   Tony：postsFinal [[＆＃34;纬度＆＃34;：53.514649900000002，＆＃34;邮政编码＆＃34;：＆＃34; OL8 2TT＆＃34;，＆＃34;标题＆＃34;：＆＃34; JDFG VBF＆＃34;，＆＃34;经度＆＃34;：-2.1052824000000001]，[＆＃34;纬度＆＃34;：50.800523599999998，＆＃34;邮政编码＆＃34;：＆＃34; PO1 5DS＆＃34;， ＆＃34; title＆＃34;：＆＃34; QWER QWE＆＃34;，＆＃34;经度＆＃34;：-1.0723248000000001]，[＆＃34;纬度＆＃34;：50.802415099999997，＆＃34;邮政编码＆ ＃34;：＆＃34; PO1 5JA＆＃34;，＆＃34; title＆＃34;：＆＃34; QWER QWE＆＃34;，＆＃34;经度＆＃34;：-1.0726989]]   Tony Places [＆＃34; OL8 2TT＆＃34;，＆＃34; PO1 5DS＆＃34;，＆＃34; PO1 5JA＆＃34;]   Tony：postsFinal [[＆＃34;纬度＆＃34;：53.514649900000002，＆＃34;邮政编码＆＃34;：＆＃34; OL8 2TT＆＃34;，＆＃34;标题＆＃34;：＆＃34; JDFG VBF＆＃34;，＆＃34;经度＆＃34;：-2.1052824000000001]，[＆＃34;纬度＆＃34;：50.800523599999998，＆＃34;邮政编码＆＃34;：＆＃34; PO1 5DS＆＃34;， ＆＃34; title＆＃34;：＆＃34; QWER QWE＆＃34;，＆＃34;经度＆＃34;：-1.0723248000000001]，[＆＃34;纬度＆＃34;：50.802415099999997，＆＃34;邮政编码＆ ＃34;：＆＃34; PO1 5JA＆＃34;，＆＃34; title＆＃34;：＆＃34; QWER QWE＆＃34;，＆＃34;经度＆＃34;：-1.0726989]]

1 个答案:

答案 0 :(得分：0)

您在使用此代码时遇到了一些问题。为了帮助您入门，最大的问题是geocodeAddressString。这是一个异步调用，并不保证您调用它的顺序。正在处理异步调用内部的索引，这是导致对象不匹配的原因。

geocodeAddressString完成块内的代码不会按照您编码的顺序执行。让我们假设你在self.places数组中有5个元素。对于每一个，您都可以调用geocodeAddressString。

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geocodeAddressString执行完成块的顺序可能是这样的：

geocodeAddressString(1)
geocodeAddressString(2)
geocodeAddressString(3)
geocodeAddressString(4)
geocodeAddressString(5)

这是因为geocodeAddressString正在做一些花费一些时间的工作，可能是网络调用。一旦它具有正确的信息，它将立即返回，这意味着对其进行5次调用将使它们以不同的速率返回。把它想象成一个有5名选手的比赛。

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