Nspredicate predicate summary array filtering fuzzy matching

Nspredicate is used to specify filtering criteria, primarily for sorting out eligible objects from the collection, or for regular matching of strings. Introduction to common methods of nspredicate [OBJC]View Plaincopy

1. 1. Create a nspredicate (equivalent to create a filter condition)
2. Nspredicate *predicate = [nspredicate predicatewithformat:@ "filter condition"];
3. 2. Determine whether the specified object meets nspredicate created filter conditions
4. [predicate Evaluatewithobject:person];
5. 3. Filter out eligible objects (return all eligible objects)
6. Nsarray *persons = [array filteredarrayusingpredicate:predicate];

Example: (The following is pseudo-code, only to explain the problem) [OBJC]View Plaincopy

2. 1. Create a Person object first
4. @interface person:nsobject{
6. NSString *name;
8. int age;
10. }
14. 2. Create an array to add multiple person objects to the array type
16. Nsarray *array=[nsarray arraywithobjects:person1,person2,person3,person4,...,Nil];
20. 3. Use Nspredicate to filter the person of the array type
22. A. Finding the person with an array of age less than 2 0
24. Nspredicate *predicate = [nspredicate predicatewithformat:@ "Age < 20"];
26. for (person*person in array) {
28. if ([predicate Evaluatewithobject:person]) { //Determines whether the specified object satisfies
30. //........................  
32. }
34. }
36. Nsarray *persons = [array filteredarrayusingpredicate:predicate]; Get all person with age less than 20

Use method mainly in these steps, the following are some common nspredicate conditions 1. Logical operation symbols >, <, =, >=, <= can be used here operators can also be used with logical operators,&&, | | , and, OR predicates are case insensitive [OBJC]View Plaincopy

1. Nspredicate *predicate = [nspredicate predicatewithformat:@ "Age > 20"];
2. Nspredicate *predicate = [nspredicate predicatewithformat:@ "name > ' abc ' && Age > 10"];
3. Nspredicate *predicate = [nspredicate predicatewithformat:@ "name > ' abc ' OR Age > 10"];

[OBJC]View Plaincopy

1. <span style="font-family:arial, Helvetica, Sans-serif;" ></span><p class="P1" >
2. </p>

2.IN

[OBJC]View Plaincopy

1. Nspredicate *predicate = [nspredicate predicatewithformat:@ "name in {' abc ', ' Def ', ' 123 '}"];

3. Start with XX--beginswith [OBJC]View Plaincopy

1. Nspredicate *predicate = [nspredicate predicatewithformat:@ "name Beginswith ' N '"]; Name the person with the N

[OBJC]View Plaincopy

1. </pre>4. End With XX--endswith</div><div></div><div><pre code_snippet_id=" 163702 "Snippet_file_name=" blog_20140120_8_9862346 "name=" code " class=" OBJC ">nspredicate * predicate = [Nspredicate predicatewithformat:@ "name ENDSWITH ' N '"]; Name the person that ends with n

5. Included--Contains [OBJC]View Plaincopy

1. Nspredicate *predicate = [nspredicate predicatewithformat:@ "name CONTAINS ' N '"]; <span style=" Font-family:arial, Helvetica, Sans-serif; >//name person</span> containing ' n '

6. Fuzzy Query--like [OBJC]View Plaincopy

1. Nspredicate *predicate = [nspredicate predicatewithformat:@ "name like ' *n* '"];  <span style= "Color:rgb (51, 51, 51); font-family:arial; font-size:14.44444465637207px; line-height:26px; " >* represents 0 or more characters </span>

7. All of the above is the property of the object match, if the array is a string how to match--self [OBJC]View Plaincopy

1. Nsarray *array=[nsarray arraywithobjects: @ "abc", @ "def", @ "Ghi",@ "JKL", nil nil];
2. Nspredicate *pre = [nspredicate predicatewithformat:@ "self== ' abc '"];
3. Nsarray *array2 = [array filteredarrayusingpredicate:pre];

8. Regular expressions [OBJC]View Plaincopy

2. (8.) Regular expression:
4. Nspredicate uses matches to match regular expressions, and the notation for regular expressions takes international components
6. The regular syntax for the for Unicode (ICU).
8. Cases:
10. NSString *regex = @ "^a.+e$";   A character that begins with a and ends with E.
12. Nspredicate *pre= [nspredicate Predicatewithformat:@ "Self MATCHES%@", regex];
14. if ([Pre evaluatewithobject: @ "Apple"]) {
16. printf ("yes\n");
18. }else{
20. printf ("no\n");
22. }

Remark: The above is my humble opinion, if there is no place, please the big points to correct, thank you!!

Nspredicate predicate summary array filtering fuzzy matching