更新值或设置的NSMutableDictionary

Question

的新重点和值我有名字的数组和想要前缀的& B. 例如，对于此用户名我希望我的的NSMutableDictionary * cellNum指望他们返回名字的计数从每个字母开始，如：“A”：“2”&“B”：“1”。

@interface ... 
{ 
    NSArray *users; 
    NSMutableDictionary *cellNum; 
} 

@implementation ... 
{ 
    users = @[@"Ali",@"Armita",@"Babak"]; 

    for (int i=0;i<users.count;i++) 
    { 
     if ([users[i] hasPrefix:@"A"]) 
     { 
      cellNum[@"a"] = @([cellNum[@"a"] intValue]+1); 
     } 
     else 
     { 
      cellNum[@"b"] = @([cellNum[@"b"] intValue]+1); 
     } 
    } 
} 

Answer 1

尝试使用此代码：

NSMutableDictionary *cellNum = [NSMutableDictionary dictionary]; 

[cellNum setObject:@(0) forKey:@"a"]; 
[cellNum setObject:@(0) forKey:@"b"]; 

NSArray* users = @[@"Ali",@"Armita",@"Babak"]; 

for (int i=0;i<users.count;i++) 
{ 
if ([users[i] hasPrefix:@"A"]) { 
cellNum[@"a"] = @([cellNum[@"a"] intValue]+1); 
} 
else { 
cellNum[@"b"] = @([cellNum[@"b"] intValue]+1); 
} 
} 

这必将给你所期望的结果：{A = 2; b = 1; }