问题描述

过滤字符串的开头是数字或符号

怎么样对字符串的开头是数字或是符号进行过滤，然后给带NSPredicate的NSArray。

举个例子：

array = {""John""Mary""Aroldo""1John""+Mary""}to newArray = {""1John ""+Mary""}

解决方案

有四种方法可以实现。每个方法都用了否定字符类，你的需求是要求数字或者符号，也就是非字母character。

- (void)testFilterArray0{    predicate = [NSPredicate predicateWithFormat:@""SELF MATCHES %@"" @""[^a-zA-Z].*""];    filtered = [unfiltered filteredArrayUsingPredicate:predicate];    STAssertTrue([filtered isEqualToArray:expected] nil);}- (void)testFilteredArray1{    predicate = [NSPredicate predicateWithFormat:@""SELF MATCHES %@"" @""[^\p{L}].*""];    filtered = [unfiltered filteredArrayUsingPredicate:predicate];    STAssertTrue([filtered isEqualToArray:expected] nil);}- (void)testFilteredArray2{    predicate = [NSPredicate predicateWithFormat:@""SELF MATCHES %@"" @""[^\p{Letter}].*""];    filtered = [unfiltered filteredArrayUsingPredicate:predicate];    STAssertTrue([filtered isEqualToArray:expected] nil);}- (void)testFilteredArray3{    predicate = [NSPredicate predicateWithFormat:@""SELF MATCHES %@"" @""[^\p{General_Category=Letter}].*""];    filtered = [unfiltered filteredArrayUsingPredicate:predicate];    STAssertTrue([filtered isEqualToArray:expected] nil);}