Question

我试图获得连续行之间的差异，例如：

dt_in <- data.table(
  Game = c(1,1,2,2,3,3,4,4),
  ID = c(1,2,3,4,5,6,7,8),
  weight = c(150,120,151,160,190,170,170,170)
)

我想计算每个ID，他们的权重比Game中的其他ID多多少少。到目前为止我所做的是：

dt_in[, d1 := diff(weight), by = list(Game)]

给出：

> dt_in
   Game ID weight  d1
1:    1  1    150 -30
2:    1  2    120 -30
3:    2  3    151   9
4:    2  4    160   9
5:    3  5    190 -20
6:    3  6    170 -20
7:    4  7    170   0
8:    4  8    170   0

但我想要的是：

> dt_in
   Game ID weight  d1 want
1:    1  1    150 -30   30
2:    1  2    120 -30  -30
3:    2  3    151   9   -9
4:    2  4    160   9    9
5:    3  5    190 -20   20
6:    3  6    170 -20  -20
7:    4  7    170   0    0
8:    4  8    170   0    0

Answer 1

我们可以获得import Foundation import UIKit class OrderProduct: NSObject, NSCoding { var uuid: String = NSUUID().UUIDString var productcode:String = "" var detail:String = "" var quantity:String = "" var barcode:String = "" var inOrderList = false func encodeWithCoder(coder: NSCoder) { coder.encodeObject(uuid, forKey: "uuid") coder.encodeObject(productcode, forKey: "productcode") coder.encodeObject(detail, forKey: "detail") coder.encodeObject(quantity, forKey: "quantity") coder.encodeObject(barcode, forKey: "barcode") coder.encodeBool(inOrderList, forKey: "inOrderList") } required init?(coder decoder: NSCoder) { super.init() if let archivedUuid = decoder.decodeObjectForKey("uuid") as? String { uuid = archivedUuid } if let archivedProductcode = decoder.decodeObjectForKey("productcode") as? String { productcode = archivedProductcode } if let archivedDetail = decoder.decodeObjectForKey("detail") as? String { detail = archivedDetail } if let archivedQuantity = decoder.decodeObjectForKey("quantity") as? String { quantity = archivedQuantity } if let archivedBarcode = decoder.decodeObjectForKey("barcode") as? String { barcode = archivedBarcode } inOrderList = decoder.decodeBoolForKey("inOrderList") } init(productcode: String, detail: String, quantity: String, barcode: String) { super.init() self.productcode = productcode self.detail = detail self.quantity = quantity self.barcode = barcode } }的权重＆＃39;按＆＃39; Game＆＃39;分组，乘以-1并连接两个值。

import Foundation
import UIKit

//MARK: - Class
class TestOrderViewController: UITableViewController{

required init?(coder decoder: NSCoder) {
    //print("init OrderViewController")
    super.init(coder: decoder)

    loadOrderProducts()
    }

    deinit {
}

//MARK: - Product Vars
    var passedProductcode = String()     //String is recieved here!
    var passedDetail = String()          //String is recieved here!
    var passedQuantity = String()        //String is recieved here!
    var passedBarcode = String()         //String is recieved here!

    var orderProducts = [OrderProduct]() //My Object model...

//MARK: - ViewDidLoad
override func viewDidLoad() {
    super.viewDidLoad()
    title = "Order List"

    orderProducts.productcode = passedProductcode //Trying to pass them but
    orderProducts.detail = passedDetail           //errors with "Value of type
    orderProducts.quantity = passedQuantity       //'[OrderProduct]' has no
    orderProducts.barcode = passedBarcode         //member 'productcode'?

    tableView.estimatedRowHeight = 80.0
    tableView.rowHeight = UITableViewAutomaticDimension
    }

// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
    // Return the number of sections.
    return 1
}

override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    // Return the number of rows in the section.

    return orderProducts.count
}

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCellWithIdentifier("OrderCell", forIndexPath: indexPath) as! OrderTableViewCell
    let orderProduct = orderProducts[indexPath.row]
    cell.productcodeLabel.text = orderProduct.productcode
    cell.detailLabel.text = orderProduct.detail
    cell.quantityLabel.text = "X \(orderProduct.quantity)"
    cell.barcodeLabel.text = orderProduct.barcode

    return cell
}

private func loadOrderProducts() {
    if let filePath = pathForOrderProducts() where NSFileManager.defaultManager().fileExistsAtPath(filePath) {
        if let archivedOrderProducts = NSKeyedUnarchiver.unarchiveObjectWithFile(filePath) as? [OrderProduct] {
            orderProducts = archivedOrderProducts
        }
    }
}

private func pathForOrderProducts() -> String? {
    let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true)

    if let documents = paths.first, let documentsURL = NSURL(string: documents) {
        return documentsURL.URLByAppendingPathComponent("orderProducts.plist").path
    }
    return nil
}

private func saveOrderProducts() {
    if let filePath = pathForOrderProducts() {
        NSKeyedArchiver.archiveRootObject(orderProducts, toFile: filePath)
        }
    }
}

@Frank的紧凑选项

diff

使用R中的数据表的连续行组之间的差异

1 个答案: