ios - NSPredicate 创建

Question

我应该如何创建一个 NSPredicate 来测试一个 NSString 是否以某种模式开头，比如“AAA”？
非常感谢你!
我试图阅读 Apple 的引用资料，但无法理解。

Answer 1

像这样:

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF BEGINSWITH[cd] %@", @"AAA"];

如果你想从数组中找到所有匹配的字符串:

for(NSString *n in [myArray filteredArrayUsingPredicate:predicate]) {
    NSLog(@"%@", n);
}

并回答您对“c”和“d”字符等的评论:

SELF is in this case NSString object

BEGINSWITH[] explanation not needed, I think.

"String comparisons are by default case and diacritic sensitive. You can modify an operator using the key characters c and d within square braces to specify case and diacritic insensitivity respectively" (quote from Apple's Predicates Programming Guide)