CoreData中NSpredicate的使用和延伸

来源：互联网发布：mac找不到搜狗输入法编辑：程序博客网时间：2024/06/06 11:24

NSPredicate在CoreData中常用作查询使用，相当于sql语句中的where查询子句。
最常用的方法为：
view sourceprint?
1.NSPredicate *ca = [NSPredicate predicateWithFormat:(NSString *), ...];

比如我们要查询student表中name=“jjy”的信息，我们可以这样去用NSPredicate
view sourceprint?
01.NSEntityDescription * emEty = [NSEntityDescription entityForName:@"student"inManagedObjectContext:self.managedObjectContext];
02.NSFetchRequest *frq = [[NSFetchRequest alloc]init];
03.
04.[frq setEntity:emEty];
05.
06.NSPredicate * cdt = [NSPredicate predicateWithFormat:@"name= %@",@"jjy"];
07.
08.[frq setPredicate:cdt];
09.
10.NSArray *objs =[self.managedObjectContext executeFetchRequest:frq error:nil];

得到的就是名称为jjy的个人信息。
当然了这个还有其他用处，在网上看大针对其他用法的总结，在这借用过来，分享给大家：
Format：
(1)比较运算符>,<,==,>=,<=,!=
可用于数值及字符串
例：@"number > 100"

(2)范围运算符：IN、BETWEEN
例：@"number BETWEEN {1,5}"
@"address IN {'shanghai','beijing'}"

(3)字符串本身:SELF
例：@“SELF == ‘APPLE’"

(4)字符串相关：BEGINSWITH、ENDSWITH、CONTAINS
例：@"name CONTAIN[cd] 'ang'" //包含某个字符串
@"name BEGINSWITH[c] 'sh'" //以某个字符串开头
@"name ENDSWITH[d] 'ang'" //以某个字符串结束
注:[c]不区分大小写[d]不区分发音符号即没有重音符号[cd]既不区分大小写，也不区分发音符号。

(5)通配符：LIKE
例：@"name LIKE[cd] '*er*'" //*代表通配符,Like也接受[cd].
@"name LIKE[cd] '???er*'"

(6)正则表达式：MATCHES
例：NSString *regex = @"^A.+e$"; //以A开头，e结尾
@"name MATCHES %@",regex

实际应用：
(1)对NSArray进行过滤
view sourceprint?
1.NSArray *array = [[NSArray alloc]initWithObjects:@"beijing",@"shanghai",@"guangzou",@"wuhan", nil];
2.NSString *string = @"ang";
3.NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF CONTAINS %@",string];
4.NSLog(@"%@",[array filteredArrayUsingPredicate:pred]);

(2)判断字符串首字母是否为字母:
view sourceprint?
1.NSString *regex = @"[A-Za-z]+";
2.NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];
3.
4.if ([predicate evaluateWithObject:aString]) {
5.}

(3)字符串替换：
view sourceprint?
01.NSError* error = NULL;
02.NSRegularExpression* regex = [NSRegularExpression regularExpressionWithPattern:@"(encoding=\")[^\"]+(\")"
03.options:0
04.error:&error];
05.NSString* sample = @"<xml encoding=\"abc\"></xml><xml encoding=\"def\"></xml><xml encoding=\"ttt\"></xml>";
06.NSLog(@"Start:%@",sample);
07.NSString* result = [regex stringByReplacingMatchesInString:sample
08.options:0
09.range:NSMakeRange(0, sample.length)
10.withTemplate:@"$1utf-8$2"];
11.NSLog(@"Result:%@", result);

(4)截取字符串如下：
view sourceprint?
01.//组装一个字符串，需要把里面的网址解析出来
02.NSString *urlString=@"<meta/><link/><title>1Q84 BOOK1</title></head><body>";
03.
04.//NSRegularExpression类里面调用表达的方法需要传递一个NSError的参数。下面定义一个
05.NSError *error;
06.
07.//http+:[^\\s]* 这个表达式是检测一个网址的。(?<=title\>).*(?=</title)截取html文章中的<title></title>中内文字的正则表达式
08.NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"(?<=title\\>).*(?=</title)" options:0 error:&error];
09.
10.if (regex != nil) {
11.NSTextCheckingResult *firstMatch=[regex firstMatchInString:urlString options:0range:NSMakeRange(0, [urlString length])];
12.
13.if (firstMatch) {
14.NSRange resultRange = [firstMatch rangeAtIndex:0];
15.
16.//从urlString当中截取数据
17.NSString *result=[urlString substringWithRange:resultRange];
18.//输出结果
19.NSLog(@"->%@<-",result);
20.}
21.
22.}

(5)判断手机号码，电话号码函数
view sourceprint?
01.//组装一个字符串，需要把里面的网址解析出来
02.NSString *urlString=@"<meta/><link/><title>1Q84 BOOK1</title></head><body>";
03.
04.//NSRegularExpression类里面调用表达的方法需要传递一个NSError的参数。下面定义一个
05.NSError *error;
06.
07.//http+:[^\\s]* 这个表达式是检测一个网址的。(?<=title\>).*(?=</title)截取html文章中的<title></title>中内文字的正则表达式
08.NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"(?<=title\\>).*(?=</title)" options:0 error:&error];
09.
10.if (regex != nil) {
11.NSTextCheckingResult *firstMatch=[regex firstMatchInString:urlString options:0range:NSMakeRange(0, [urlString length])];
12.
13.if (firstMatch) {
14.NSRange resultRange = [firstMatch rangeAtIndex:0];
15.
16.//从urlString当中截取数据
17.NSString *result=[urlString substringWithRange:resultRange];
18.//输出结果
19.NSLog(@"->%@<-",result);
20.}
21.
22.}
23.
24.(5)判断手机号码，电话号码函数
25.[cpp] view plaincopy
26.// 正则判断手机号码地址格式
27.- (BOOL)isMobileNumber:(NSString *)mobileNum
28.{
29./**
30.* 手机号码
31.* 移动：134[0-8],135,136,137,138,139,150,151,157,158,159,182,187,188
32.* 联通：130,131,132,152,155,156,185,186
33.* 电信：133,1349,153,180,189
34.*/
35.NSString * MOBILE = @"^1(3[0-9]|5[0-35-9]|8[025-9])\\d{8}$";
36./**
37.10         * 中国移动：China Mobile
38.11         * 134[0-8],135,136,137,138,139,150,151,157,158,159,182,187,188
39.12         */
40.NSString * CM = @"^1(34[0-8]|(3[5-9]|5[017-9]|8[278])\\d)\\d{7}$";
41./**
42.15         * 中国联通：China Unicom
43.16         * 130,131,132,152,155,156,185,186
44.17         */
45.NSString * CU = @"^1(3[0-2]|5[256]|8[56])\\d{8}$";
46./**
47.20         * 中国电信：China Telecom
48.21         * 133,1349,153,180,189
49.22         */
50.NSString * CT = @"^1((33|53|8[09])[0-9]|349)\\d{7}$";
51./**
52.25         * 大陆地区固话及小灵通
53.26         * 区号：010,020,021,022,023,024,025,027,028,029
54.27         * 号码：七位或八位
55.28         */
56.// NSString * PHS = @"^0(10|2[0-5789]|\\d{3})\\d{7,8}$";
57.
58.NSPredicate *regextestmobile = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", MOBILE];
59.NSPredicate *regextestcm = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", CM];
60.NSPredicate *regextestcu = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", CU];
61.NSPredicate *regextestct = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", CT];
62.
63.if (([regextestmobile evaluateWithObject:mobileNum] == YES)
64.|| ([regextestcm evaluateWithObject:mobileNum] == YES)
65.|| ([regextestct evaluateWithObject:mobileNum] == YES)
66.|| ([regextestcu evaluateWithObject:mobileNum] == YES))
67.{
68.if([regextestcm evaluateWithObject:mobileNum] == YES) {
69.NSLog(@"China Mobile");
70.} else if([regextestct evaluateWithObject:mobileNum] == YES) {
71.NSLog(@"China Telecom");
72.} else if ([regextestcu evaluateWithObject:mobileNum] == YES) {
73.NSLog(@"China Unicom");
74.} else {
75.NSLog(@"Unknow");
76.}
77.
78.return YES;
79.}
80.else
81.{
82.return NO;
83.}
84.}

(6)邮箱验证、电话号码验证:
view sourceprint?
01.//是否是有效的正则表达式
02.
03.+(BOOL)isValidateRegularExpression:(NSString *)strDestination byExpression:(NSString *)strExpression
04.
05.{
06.
07.NSPredicate *predicate = [NSPredicatepredicateWithFormat:@"SELF MATCHES %@", strExpression];
08.
09.return [predicate evaluateWithObject:strDestination];
10.
11.}
12.
13.//验证email
14.+(BOOL)isValidateEmail:(NSString *)email {
15.
16.NSString *strRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{1,5}";
17.
18.BOOL rt = [CommonTools isValidateRegularExpression:email byExpression:strRegex];
19.
20.return rt;
21.
22.}
23.
24.//验证电话号码
25.+(BOOL)isValidateTelNumber:(NSString *)number {
26.
27.NSString *strRegex = @"[0-9]{1,20}";
28.
29.BOOL rt = [CommonTools isValidateRegularExpression:number byExpression:strRegex];
30.
31.return rt;
32.
33.}

(7)NSDate进行筛选
view sourceprint?
01.//日期在十天之内:
02.NSDate *endDate = [[NSDate date] retain];
03.NSTimeInterval timeInterval= [endDate timeIntervalSinceReferenceDate];
04.timeInterval -=3600*24*10;
05.NSDate *beginDate = [[NSDate dateWithTimeIntervalSinceReferenceDate:timeInterval] retain];
06.//对coredata进行筛选(假设有fetchRequest)
07.NSPredicate *predicate_date =
08.[NSPredicate predicateWithFormat:@"date >= %@ AND date <= %@", beginDate,endDate];
09.
10.[fetchRequest setPredicate:predicate_date];
11.//释放retained的对象
12.[endDate release];
13.[beginDate release];

0 0