OC语言 - NSPredicate
作者：互联网
NSPredicate
1 - NSPredicate 主要用来指定过滤器的条件：该对象可以准确的描述所需条件，对每个对象通过谓词进行筛选，判断是否与条件相匹配
2 - 谓词是指在计算机中表示计算真假值的函数，原理和用法都类似于 SQL 查询中的 where，作用相当于数据库的过滤取。主要用于从集合中分拣出符合条件的对象，也可以用于字符串的正则匹配。起始谓词就是判断一个对象是否符合某个过滤条件，返回 bool 类型，如果是一系列的对象那么就使用一个循环
3 - 常规 API
① 比较运算符 > 、< 、== 、 >= 、<= 、!=
@"number >= 99"
② 逻辑运算符：AND、OR、NOT，这几个运算符计算并、或、非的结果
③ 范围运算符：IN 、BETWEEN
@"number BETWEEN {1,5}";
@"address IN {'shanghai','nanjing'}"
④ 字符串本身：SELF
@"SELF == 'APPLE'"
⑤ 字符串相关：BEGINSWITH、ENDSWITH、CONTAINS
@"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
⑥ 通配符：LIKE
@"name LIKE[cd] '*er*'" // 代表通配符，Like 也接受 [cd]
⑦ 正则表达式：MATCHES
NSString *regex = @"^A.+e$";// 以 A 开头，并以 e 结尾 @"name MATCHES %@",regex
4 - 代码示例：新建 Person 文件充当数据
// - Person.h
1 #import <Foundation/Foundation.h> 2 @interface Person : NSObject 3 4 @property (nonatomic, copy)NSString *name; 5 @property (nonatomic ,assign)NSInteger age; 6 7 @end
// - Person.m
1 #import "Person.h"
2 @implementation Person
3 - (NSString *)description{
4
5 return [NSString stringWithFormat:@"name= %@ sex = %ld", _name, _age];
6 }
7
8 @end
// - main.m
1 #import <Foundation/Foundation.h>
2 #import "Person.h"
3 int main(int argc, const char * argv[]) {
4
5 NSMutableArray * array = [NSMutableArray arrayWithCapacity:1];
6
7 // 遍历几条数据
8 for (int i = 0; i < 10; i++) {
9
10 Person * per = [[Person alloc] init];
11
12 // 配置姓名
13 if (i < 5) {
14 per.name = [NSString stringWithFormat:@"jack-%d",i];
15 }
16 else{
17 per.name = [NSString stringWithFormat:@"tom-%d",i];
18 }
19 // 配置年龄
20 per.age = 20 + i;
21 [array addObject:per];
22 }
23
24
25
26 // 过滤年龄
27 NSPredicate *predict01 = [NSPredicate predicateWithFormat:@"age < %d", 25];
28 NSLog(@"%@",predict01);// 输出：age < 25
29 // 开始过滤
30 for (Person *per in array) {
31
32 BOOL result = [predict01 evaluateWithObject:per];
33 if (result) {
34 NSLog(@"%@",per);
35 }
36 }
37
38 NSLog(@"~~~~~~~~~~~~~~~~ 或 ~~~~~~~~~~~~~~~~~~~");
39 // 或
40 NSPredicate * predict02 = [NSPredicate predicateWithFormat:@"name == 'jack-0' || name == 'jack-4'"];
41 NSLog(@"%@",predict02);
42 for (Person * per in array) {
43 BOOL result = [predict02 evaluateWithObject:per];
44 if (result) {
45 NSLog(@"%@",per);
46 }
47 }
48 NSLog(@"~~~~~~~~~~~~~~ 范围运算 ~~~~~~~~~~~~~~~");
49 // 范围运算
50 NSPredicate * predict03 = [NSPredicate predicateWithFormat:@"name IN {'jack-0','jack-2', 'tom-6', 'tom-8'}"];
51 NSLog(@"%@",predict03);
52 for (Person * per in array) {
53 BOOL result = [predict03 evaluateWithObject:per];
54 if (result) {
55 NSLog(@"%@",per);
56 }
57 }
58
59 NSLog(@"~~~~~~~~~~~~~~~ beginswith、endswith、contains~~~~~~~~~~~~~~~~~");
60 // beginswith、endswith、contains
61 NSPredicate *predict04 = [NSPredicate predicateWithFormat:@"name beginswith 'j'"];
62 NSLog(@"%@",predict04);
63 for (Person *per in array) {
64 BOOL result = [predict04 evaluateWithObject:per];
65 if (result) {
66 NSLog(@"%@",per);
67 }
68 }
69
70 NSPredicate *predict05 = [NSPredicate predicateWithFormat:@"name contains 'o'"];
71 NSLog(@"%@",predict05);
72 for (Person *per in array) {
73 BOOL result = [predict05 evaluateWithObject:per];
74 if (result) {
75 NSLog(@"%@",per);
76 }
77 }
78
79 NSLog(@"~~~~~~~~~~~~~~ like ~~~~~~~~~~~~~~~~~~");
80 // like
81 //NSPredicate * predicate06 = [NSPredicate predicateWithFormat:@"self.name like '*jack*'"];
82 NSPredicate * predicate06 = [NSPredicate predicateWithFormat:@"self.name like 'jack*'"];
83 NSLog(@"%@",predicate06);
84 for (Person *per in array) {
85 BOOL result = [predicate06 evaluateWithObject:per];
86 if (result) {
87
88 NSLog(@"%@",per);
89 }
90 }
91
92 NSLog(@"~~~~~~~~~~~~~ 以 t 开头并以 5 结尾 ~~~~~~~~~~~~~~~");
93
94 // 以 t 开头并以 5 结尾
95 NSString * regex = @"^t.+5$";
96 NSPredicate *predicate07 = [NSPredicate predicateWithFormat:@"self.name matches %@", regex];
97 NSLog(@"%@",predicate07);
98 for (Person * per in array){
99 BOOL result = [predicate07 evaluateWithObject:per];
100 if (result) {
101 NSLog(@"%@",per);
102 }
103 }
104
105 NSLog(@"~~~~~~~~~~~ 两数组交集 ~~~~~~~~~~~~");
106
107 // 两数组交集
108 NSArray *array1 = [NSArray arrayWithObjects:@"abc1", @"abc2", nil];
109 NSArray *array2 = [NSArray arrayWithObjects:@"a1", @"abc1", @"abc4", @"abc2", nil];
110 NSPredicate *thePredicate = [NSPredicate predicateWithFormat:@"SELF IN %@", array1];
111 NSArray *resultArray = [array2 filteredArrayUsingPredicate:thePredicate];
112 NSLog(@"%@",resultArray);
113
114 NSLog(@"~~~~~~~~~~~ 过滤数组 ~~~~~~~~~~~~~~");
115
116 // 过滤数组
117 NSArray *arrayFilter = [NSArray arrayWithObjects:array[0], array[3], nil];
118 NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF IN %@", arrayFilter];
119 // 可变数组过滤没有返回值；不可变数组过滤返回不可变数组
120 // [array filterUsingPredicate:predicate];
121 // NSLog(@"%@",array);
122
123 // 遍历出符合过滤条件的对象
124 NSArray *arrayFilter01 = [NSArray arrayWithObjects:array[0], array[3], nil];
125 for (int i = 0; i < arrayFilter01.count; i++) {
126
127 Person * filterPerson = [arrayFilter01 objectAtIndex:i];
128 NSPredicate * predicate = [NSPredicate predicateWithFormat:@"self.name contains %@", filterPerson.name];
129 [array filterUsingPredicate:predicate];// 要注掉上行过滤数组语句，否则 array 过滤后内容已改变，执行崩溃
130 NSLog(@"%@",filterPerson);
131 }
132
133 return 0;
134 }
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标签：NSPredicate,name,NSLog,per,C语言,Person,array 来源： https://www.cnblogs.com/self-epoch/p/16061696.html