如何优化庞大的 "if else" 逻辑语句
2021-09-03 本文已影响0人
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[推荐表驱动法]！
优点：
1> 用数据代替逻辑，容易维护
2> 可以把表中的数据存放在文件中，运行时读取，减少代码体量。数据变更时只需要修改文件
3> 降低复杂度
场景1 根据status的值判断对应的result的值:
- 一般思路
if ([status isEqualToString:@"0"]) {
result = @"0000";
}else if ([status isEqualToString:@"1"]){
result = @"1111";
}else if ([status isEqualToString:@"2"]){
result = @"2222";
}else if ([status isEqualToString:@"3"]){
result = @"3333";
}else if ([status isEqualToString:@"4"]){
result = @"4444";
}else if ([status isEqualToString:@"5"]){
result = @"5555";
}else if ([status isEqualToString:@"6"]){
result = @"6666";
}
可以看出逻辑是有规律，那么怎么去掉if-else呢，可以换个方式实现
用表驱动方法直接访问得到一样的结果
NSDictionary *dic = @{
@"0":@"0000",
@"1":@"1111",
@"2":@"2222",
@"3":@"3333",
@"4":@"4444",
@"5":@"5555",
@"6":@"6666",
};
result = dic[status]
场景2 进行tableview点击方法中的跳转
一般写法 根据indexPath.row判断或者判断对应model的属性
if (indexPath.row == 0) {
ViewController *vc1 = [ViewController new];
vc1.index = 2;
[weakSelf.navigationController pushViewController:vc1 animated:YES];
}else if (indexPath.row == 1){
ViewController *vc2 = [ViewController new];
vc2.index = 2;
[weakSelf.navigationController pushViewController:vc2 animated:YES];
}else if (indexPath.row == 3){
ViewController *vc3 = [ViewController new];
vc3.index = 2;
[weakSelf.navigationController pushViewController:vc3 animated:YES];
}else if (indexPath.row == 3){
ViewController *vc4 = [ViewController new];
vc4.index = 2;
[weakSelf.navigationController pushViewController:vc4 animated:YES];
}else if (indexPath.row == 4){
ViewController *vc5 = [ViewController new];
vc5.index = 2;
[weakSelf.navigationController pushViewController:vc5 animated:YES];
}
用表驱动法优化后的代码
//只需要维护这个字典即可
NSArray *arr = @[
@{
//跳转的类名
@"only_className":@"ViewController",
//携带的参数
@"index":@(2),
},
@{
@"only_className":@"ViewController",
@"index":@(2),
},
@{
@"only_className":@"ViewController",
@"index":@(2),
},
@{
@"only_className":@"ViewController",
@"index":@(2),
},
@{
@"only_className":@"ViewController",
@"index":@(2),
},
];
NSDictionary *keyDic = arr[indexPath.row];
YHBaseViewController *vc = [[NSClassFromString((NSString *) keyDic[@"only_className"])alloc] init];
[self.navigationController pushViewController:vc animated:YES];
场景3 每天做不同的事情 (1号健身 2号钓鱼 3号看NBA 4号敲代码 5号休息 6号睡觉 )
一般写法,if(1号) doSomething if(2号) doSomething
wBaseModel *myModel = model;
if ([myModel.imageName isEqualToString:@"1"]) {
[self fitnessAction:@{
@"paramOne":@"去健身",
}] ;
}else if ([myModel.imageName isEqualToString:@"2"]) {
[self fishingAction];
}else if ([myModel.imageName isEqualToString:@"3"]) {
[self WatchNBAAction];
}else if ([myModel.imageName isEqualToString:@"4"]) {
[self codeAction];
}else if ([myModel.imageName isEqualToString:@"5"]) {
[self releaxAction];
}else if ([myModel.imageName isEqualToString:@"6"]) {
[self sleepAction];
}
索引访问表优化代码
// 同样管理字典即可
NSDictionary *dataDic = @{
//唯一判断标志
@"1":@{
//方法名
@"mySelectorName":@"fitnessAction:",
//传入的参数
@"paramOne":@"去健身",
},
@"2":@{
@"mySelectorName":@"fishingAction",
},
@"3":@{
@"mySelectorName":@"WatchNBAAction",
},
@"4":@{
@"mySelectorName":@"codeAction",
},
@"5":@{
@"mySelectorName":@"releaxAction:",
},
@"6":@{
@"mySelectorName":@"sleepAction",
},
};
NSDictionary *keyDic = dataDic[myModel.imageName];
if (keyDic) {
id obj = [WMZStrategy performIDSelector:keyDic[@"mySelectorName"] Tagert:self withParam:keyDic];
if(obj)
NSLog(@"结果 %@",obj);
}
场景4 根据数值判断属于哪个范围
0-59是差 60-69是及格 70-79是中等 80-89是良好 90 - 99分是优秀 100是特优
//一般思路
NSInteger grade = 30;
if (grade > 0 && grade <= 59) {
NSLog(@"差");
}else if (grade>59&&grade<70) {
NSLog(@"及格");
}else if (grade>=70&&grade<80) {
NSLog(@"中等");
}else if (grade>=80&&grade<90) {
NSLog(@"良好");
}else if (grade>=90&&grade<100) {
NSLog(@"优秀");
}else{
NSLog(@"特优");
}
这种带范围的判断可以用表驱动法中的阶梯访问
NSArray *gradeArr = @[@(59),@(69),@(79),@(89),@(99),@(100)];
NSArray *levelArr = @[@"差",@"及格",@"中等",@"良好",@"优秀",@"特优"];
for( int i = 0 ; i < gradeArr.count ; i++){
if(grade <= [gradeArr[i] integerValue]){
NSLog(@"%@",levelArr[i]);
return levelArr[i];
}
}
