使用pyparsing，我有规则用括号（），+，-，*和/解析数学表达式。这些操作可以嵌套，并且解析器知道如何实现。功劳归于PaulMcG。
表达式可以使用import UIKit
class CategoryViewController: UIViewController {
//MARK: IBOutlets
@IBOutlet weak var store_bar: UIViewX!
@IBOutlet weak var store_title: UIButton!
@IBOutlet weak var category_title: UIButton!
@IBOutlet weak var category_bar: UIViewX!
@IBOutlet weak var categoryColView: UICollectionView!
var selectedBtnIndex:Int = 1
var categoryData = [ModelCategories]()
var storeData = [ModelStore]()
override func viewDidLoad() {
super.viewDidLoad()
// register collectionview cell
self.categoryColView.register(UINib(nibName: "CategoryCell1", bundle: nil), forCellWithReuseIdentifier: "CategoryCell1")
self.categoryColView.register(UINib(nibName: "StoresCell", bundle: nil), forCellWithReuseIdentifier: "StoresCell")
self.store_bar.isHidden = true
self.getCategoriesList()
self.getStoreList()
}
override var preferredStatusBarStyle: UIStatusBarStyle {
return .lightContent
}
@objc func click_Category(sender: UIButton!) {
UIView.animate(withDuration: 1.0) {
sender.isSelected = !sender.isSelected
}
}
@objc func click_store(sender: UIButton!) {
UIView.animate(withDuration: 1.0) {
sender.isSelected = !sender.isSelected
}
}
//MARK: IBActions
@IBAction func categoriesData(_ sender: UIButton) {
selectedBtnIndex = 1
self.categoryColView.isHidden = false
self.store_bar.isHidden = true
self.category_title.setTitleColor(UIColor.black, for: .normal)
self.category_bar.isHidden = false
self.store_title.setTitleColor(UIColor(rgb: 0xAAAAAA), for: .normal)
self.categoryColView.reloadData()
}
@IBAction func storeData(_ sender: UIButton) {
selectedBtnIndex = 2
self.categoryColView.isHidden = false
self.store_bar.isHidden = false
self.store_title.setTitleColor(UIColor.black, for: .normal)
self.category_bar.isHidden = true
self.category_title.setTitleColor(UIColor(rgb: 0xAAAAAA), for: .normal)
self.categoryColView.reloadData()
}
@IBAction func showHomeScreen(_ sender: UIButton) {
let vc = self.storyboard?.instantiateViewController(withIdentifier: "HomeViewController") as! HomeViewController
self.navigationController?.pushViewController(vc, animated:true)
}
@IBAction func toSearchPage(_ sender: UIButton) {
let vc = self.storyboard?.instantiateViewController(withIdentifier: "SearchPageController") as! SearchPageController
self.navigationController?.pushViewController(vc, animated:true)
}
func getCategoriesList() {
if ApiUtillity.sharedInstance.isReachable() {
ApiUtillity.sharedInstance.StartProgress(view: self.view)
APIClient<ModelBaseCategoryList>().API_GET(Url: SD_GET_CategoriesList, Params: [:], Authentication: true, Progress: true, Alert: true, Offline: false, SuperVC: self, completionSuccess: { (modelResponse) in
ApiUtillity.sharedInstance.StopProgress(view: self.view)
if(modelResponse.success == true) {
self.categoryData.removeAll()
let resul_array_tmp_new = modelResponse.categories! as NSArray
if resul_array_tmp_new.count > 0 {
for i in modelResponse.categories! {
self.categoryData.append(i)
}
}
}
else {
self.view.makeToast(modelResponse.message)
}
ApiUtillity.sharedInstance.StopProgress(view: self.view)
self.categoryColView.reloadData()
}) { (failed) in
ApiUtillity.sharedInstance.StopProgress(view: self.view)
self.view.makeToast(failed.localizedDescription)
}
}
else
{
self.view.makeToast("No Internet Connection..")
}
}
func getStoreList() {
if ApiUtillity.sharedInstance.isReachable() {
ApiUtillity.sharedInstance.StartProgress(view: self.view)
APIClient<ModelBaseStoreList>().API_GET(Url: SD_GET_StoreList, Params: [:], Authentication: true, Progress: true, Alert: true, Offline: false, SuperVC: self, completionSuccess: { (modelResponse) in
ApiUtillity.sharedInstance.StopProgress(view: self.view)
if(modelResponse.success == true) {
self.storeData.removeAll()
let resul_array_tmp_new = modelResponse.store! as NSArray
if resul_array_tmp_new.count > 0 {
for i in modelResponse.store! {
self.storeData.append(i)
}
}
}
else {
self.view.makeToast(modelResponse.message)
}
ApiUtillity.sharedInstance.StopProgress(view: self.view)
self.categoryColView.reloadData()
}) { (failed) in
ApiUtillity.sharedInstance.StopProgress(view: self.view)
self.view.makeToast(failed.localizedDescription)
}
}
else
{
self.view.makeToast("No Internet Connection..")
}
}
}
//MARK: Delegate and Data Source Methods
extension CategoryViewController: UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
if selectedBtnIndex == 1{
return categoryData.count
}else {
return storeData.count
}
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
if selectedBtnIndex == 1{
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CategoryCell1", for: indexPath) as! CategoryCell1
let dict = categoryData[indexPath.row]
if let catName = dict.name, catName.count != 0 {
cell.categoryName.text = catName
}
if let catOffersCount = dict.count {
if catOffersCount <= 1 {
cell.catOfferCount.text = "\(catOffersCount)"+" "+"Offer"
cell.categoryImage.image = UIImage(named: "tickets")
}else {
cell.catOfferCount.text = "\(catOffersCount)"+" "+"Offers"
}
}
if dict.slug == "mens" {
cell.categoryImage.image = UIImage(named: "MENS")
} else if dict.slug == "electronics" {
cell.categoryImage.image = UIImage(named: "ELECTRONICS")
}else if dict.slug == "beauty" {
cell.categoryImage.image = UIImage(named: "BEAUTY")
}else if dict.slug == "fashion" {
cell.categoryImage.image = UIImage(named: "FASHION")
}else if dict.slug == "kids-clothing" {
cell.categoryImage.image = UIImage(named: "KIDS FASHION")
}else if dict.slug == "travel" {
cell.categoryImage.image = UIImage(named: "TRAVEL")
}else if dict.slug == "womens-apparels" {
cell.categoryImage.image = UIImage(named: "WOMENS APPARELS")
}else if dict.slug == "eyewear" {
cell.categoryImage.image = UIImage(named: "EYEWEAR")
}else {
cell.categoryImage.image = UIImage(named: "tickets")
}
cell.btn_click.tag = indexPath.row
cell.btn_click.setImage(#imageLiteral(resourceName: "image_unchecked"), for: .normal)
cell.btn_click.setImage(#imageLiteral(resourceName: "image_checked"), for: .selected)
cell.btn_click.addTarget(self, action: #selector(self.click_Category), for: .touchUpInside)
return cell
}else {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "StoresCell", for: indexPath) as! StoresCell
let dict = storeData[indexPath.row]
if let storeName = dict.name, storeName.count != 0 {
cell.storeName.text = storeName
}
if let storeOfferCount = dict.count {
cell.storeOfferCount.text = "\(storeOfferCount)"+" "+"Offers"
}
cell.store_btn_click.tag = indexPath.row
cell.store_btn_click.setImage(#imageLiteral(resourceName: "image_unchecked"), for: .normal)
cell.store_btn_click.setImage(#imageLiteral(resourceName: "image_checked"), for: .selected)
cell.store_btn_click.addTarget(self, action: #selector(self.click_store), for: .touchUpInside)
return cell
}
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
if selectedBtnIndex == 1{
return CGSize(width: (UIScreen.main.bounds.width) / 3, height: 93)
}else {
return CGSize(width: (UIScreen.main.bounds.width) / 3, height: 93)
}
}
关键字通过以下方式进行逻辑运算：
iif条件具有常规运算符=，> =，<=，>，<，<>，＆，|
有一种从字符串表达式计算结果的方法。但是由于条件可以具有嵌套条件，因此我找不到找到最终值的方法。
那么，有什么方法可以指示pyparsing使用逻辑运算和alonside数学运算来计算此最终值？还是有什么方法可以消除条件并将原始表达式返回为单个数学表达式，然后能够计算最终值？
PS：我正在使用python 3.6.7和Linux Mint 19.1。