iOS小技能：NSPredicate在正则表达式的应用

引言

日常开发中，优雅高效的代码离不开Predicate的应用。

格式化字符串可以被看作三部分：左手表达式、逻辑符号和右手表达式。

其中，左手表达式是一个对象的属性键值（键路径）；逻辑符号是一个基本的逻辑运算符；右手表达式是约束范围。

I 前置知识

Predicate Format String Syntax

1.1 Parser Basics

• Two important format specifiers are %@ and %K.

%@ is a var arg substitution for an object value—often a string, number, or date. %K is a var arg substitution for a key path.

NSString *attributeName  = @"firstName";
NSString *attributeValue = @"siting";
NSPredicate *predicate   = [NSPredicate predicateWithFormat:@"%K like %@",
        attributeName, attributeValue];

1.2 Basic Comparisons

=, ==The left-hand expression is equal to the right-hand expression.>=, =>The left-hand expression is greater than or equal to the right-hand expression.<=, =<The left-hand expression is less than or equal to the right-hand expression.>The left-hand expression is greater than the right-hand expression.<The left-hand expression is less than the right-hand expression.!=, <>The left-hand expression is not equal to the right-hand expression.

BETWEEN

The left-hand expression is between, or equal to either of, the values specified in the right-hand side. The right-hand side is a two value array (an array is required to specify order) giving upper and lower bounds. For example, 1 BETWEEN { 0 , 33 }, or $INPUT BETWEEN {

UPPER }.

In Objective-C, you could create a BETWEEN predicate as shown in the following example:

NSPredicate *betweenPredicate =
    [NSPredicate predicateWithFormat: @"attributeName BETWEEN %@", @[@1, @10]];
NSDictionary *dictionary = @{ @"attributeName" : @5 };
 
BOOL between = [betweenPredicate evaluateWithObject:dictionary];
if (between) {
    NSLog(@"between");
}

1.3 Basic Compound Predicates

AND, &&Logical AND.OR, ||Logical OR.NOT, !Logical NOT.

1.4 String Comparisons

逻辑运算符与SQL语句中的语法基本相对应，除了最基本的逻辑运算符之外，还有逻辑词IN、CONTAINS、like等。它们的使用情况如下：

BEGINSWITHThe left-hand expression begins with the right-hand expression.CONTAINSThe left-hand expression contains the right-hand expression.ENDSWITHThe left-hand expression ends with the right-hand expression.LIKE

The left hand expression equals the right-hand expression: ? and * are allowed as wildcard characters, where ? matches 1 character and * matches 0 or more characters.

MATCHES

The left hand expression equals the right hand expression using a regex-style comparison according to ICU v3 (for more details see the ICU User Guide for Regular Expressions).

UTI-CONFORMS-TO

The left hand argument to this operator is an expression that evaluates to a universal type identifier (UTI) you want to match. The right hand argument is an expression that evaluates to a UTI. The comparison evaluates to TRUE if the UTI returned by the left hand expression conforms to the UTI returned by the right hand expression. For information on which types conform to a given type, see System-Declared Uniform Type Identifiers in Uniform Type Identifiers Reference.

The clause A UTI-CONFORMS-TO B provides the same result as employing the UTTypeConformsTo method as follows:

UTTypeConformsTo (A, B)

When evaluating attachments in an app extension item (of type NSExtensionItem), you could use a statement similar to the following:

SUBQUERY (
    extensionItems,
    $extensionItem,
    SUBQUERY (
        $extensionItem.attachments,
        $attachment,
        ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "com.adobe.pdf"
    ).@count == $extensionItem.attachments.@count
).@count == 1

UTI-EQUALS

The left hand argument to this operator is an expression that evaluates to a universal type identifier (UTI) you want to match. The right hand argument is an expression that evaluates to a UTI. The comparison evaluates to TRUE if the UTI returned by the left hand expression equals the UTI returned by the right hand expression. The clause A UTI-EQUALS B provides the same result as employing the UTTypeEqual method as follows:

UTTypeEqual (A, B)

1.5 Aggregate Operations

ANY, SOME

Specifies any of the elements in the following expression. For example ANY children.age < 18.

ALL

Specifies all of the elements in the following expression. For example ALL children.age < 18.

NONE

Specifies none of the elements in the following expression. For example, NONE children.age < 18. This is logically equivalent to NOT (ANY ...).

IN

Equivalent to an SQL IN operation, the left-hand side must appear in the collection specified by the right-hand side.

For example, name IN { 'Ben', 'Melissa', 'Nick' }. The collection may be an array, a set, or a dictionary—in the case of a dictionary, its values are used. In Objective-C, you could create a IN predicate as shown in the following example:

NSPredicate *inPredicate =
            [NSPredicate predicateWithFormat: @"attribute IN %@", aCollection];

where aCollection may be an instance of NSArray, NSSet, NSDictionary, or of any of the corresponding mutable classes.

array[index]

Specifies the element at the specified index in the array array.

array[FIRST]

Specifies the first element in the array array.

array[LAST]

Specifies the last element in the array array.

array[SIZE]

Specifies the size of the array array.

1.6 Identifiers

C style identifier

Any C style identifier that is not a reserved word.

#symbol

Used to escape a reserved word into a user identifier.

[\]{octaldigit}{3}

Used to escape an octal number ( \ followed by 3 octal digits).

[\][xX]{hexdigit}{2}

Used to escape a hex number ( \x or \X followed by 2 hex digits).

[\][uU]{hexdigit}{4}

Used to escape a Unicode number ( \u or \U followed by 4 hex digits).

1.7 Literals

FALSE, NO

Logical false.

TRUE, YES

Logical true.

NULL, NIL

A null value.

SELF

Represents the object being evaluated.

"text"

A character string.

'text'

A character string.

Comma-separated literal array

For example, { 'comma', 'separated', 'literal', 'array' }.

Standard integer and fixed-point notations

For example, 1, 27, 2.71828, 19.75.

Floating-point notation with exponentiation

For example, 9.2e-5.

0x

Prefix used to denote a hexadecimal digit sequence.

0o

Prefix used to denote an octal digit sequence.

0b

Prefix used to denote a binary digit sequence.

1.8 Reserved Words

AND, OR, IN, NOT, ALL, ANY, SOME, NONE, LIKE, CASEINSENSITIVE, CI, MATCHES, CONTAINS, BEGINSWITH, ENDSWITH, BETWEEN, NULL, NIL, SELF, TRUE, YES, FALSE, NO, FIRST, LAST, SIZE, ANYKEY, SUBQUERY, FETCH, CAST, TRUEPREDICATE, FALSEPREDICATE, UTI-CONFORMS-TO, UTI-EQUALS,

II NSPredicate在正则表达式的应用

2.1 商品分类名称

仅支持数字、字母、中文、斜杠\、横杠",且不能以符号开头

“-”这个连接符需要转义-,否则报如下的错误

 thread 1: "Can't do regex matching, reason: Can't open pattern U_REGEX_MISSING_CLOSE_BRACKET (string U, pattern ^[0-9a-zA-Z一-龥][0-9a-zA-Z一-龥-\\]{0,}$, case 0, canon 0)"

OC正确的写法：\\\表示斜杠\ 转义符

\-代表横杆- 连接符

+ (BOOL)checkProductClassName: (NSString *) name
{
    NSString *pattern = @"^[0-9a-zA-Z\u4E00-\u9FA5][0-9a-zA-Z\u4E00-\u9FA5\\\\-]{0,}$";//
    NSLog(@"KN-pattern:%@",pattern);//2022-07-22 11:01:26.641648+0800 retail[5321:1883667] KN-pattern:^[0-9a-zA-Z一-龥][0-9a-zA-Z一-龥\\-]{0,}$
    
    NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", pattern];
    BOOL isMatch = [pred evaluateWithObject:name];
    return isMatch;
      
}

js的写法：

  pattern: /^[0-9a-zA-Z\u4E00-\u9FA5][0-9a-zA-Z\u4E00-\u9FA5-\\]{0,}$/,

2.2 基本校验例子

正则匹配用户密码6-16位数字和字母组合

+ (BOOL)checkPassword:(NSString *) password
{
    NSString *pattern = @"^(?![0-9]+$)(?![a-zA-Z]+$)[a-zA-Z0-9]{6,16}";
    
    NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", pattern];
    
    BOOL isMatch = [pred evaluateWithObject:password];
    return isMatch;
      
}

正则匹配手机号

+ (BOOL)checkTelNumber:(NSString *) telNumber
{
    NSString *pattern = @"^1+[3578]+\\d{9}";
    NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", pattern];
    BOOL isMatch = [pred evaluateWithObject:telNumber];
    return isMatch;
}
  
  
 #pragma 正则匹员工号,12位的数字
+ (BOOL)checkEmployeeNumber : (NSString *) number
{
    NSString *pattern = @"^[0-9]{12}";
      
    NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", pattern];
    BOOL isMatch = [pred evaluateWithObject:number];
    return isMatch;
      
}

正则匹配用户姓名,20位的中文或英文

+ (BOOL)checkUserName : (NSString *) userName
{
    NSString *pattern = @"^[a-zA-Z\u4E00-\u9FA5]{1,20}";
    NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", pattern];
    BOOL isMatch = [pred evaluateWithObject:userName];
    return isMatch;
      
}
  
  
#pragma 正则匹配用户身份证号15或18位
+ (BOOL)checkUserIdCard: (NSString *) idCard
{
    NSString *pattern = @"(^[0-9]{15}$)|([0-9]{17}([0-9]|X)$)";
    NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", pattern];
    BOOL isMatch = [pred evaluateWithObject:idCard];
    return isMatch;
}
  
  

正则匹配URL

+ (BOOL)checkURL : (NSString *) url
{
    NSString *pattern = @"^[0-9A-Za-z]{1,50}";
    NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", pattern];
    BOOL isMatch = [pred evaluateWithObject:url];
    return isMatch;
      
}

2.3 限制UITextField只能输入金额

+ (BOOL)isAmoutshouldChangeCharactersInRange:(NSString*)str{
    //匹配以0开头的数字
    NSPredicate * predicate0 = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",@"^[0][0-9]+$"];
    //匹配两位小数、整数
    NSPredicate * predicate1 = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",@"^(([1-9]{1}[0-9]*|[0])\.?[0-9]{0,2})$"];
    return ![predicate0 evaluateWithObject:str] && [predicate1 evaluateWithObject:str] ? YES : NO;
    
}


/**
 限制UITextField只能输入金额的正则表达式
 @param textField <#textField description#>
 @param range <#range description#>
 @param string <#string description#>
 @return <#return value description#>
 */
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{

    
        NSInteger len = range.length > 0?([textField.text length] - range.length): ([textField.text length] + [string length]);
    
        if(len > 20){
            return false;
        }
    ////
    NSString * str = [NSString stringWithFormat:@"%@%@",textField.text,string];

    return [QCT_Common isAmoutshouldChangeCharactersInRange:str];
    
    
    
    
}

2.4 Url格式校验

+(BOOL)isUrl:(NSString *)url{
    NSString *regex =@"[a-zA-z]+://[^\\s]*";
    NSPredicate *urlTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",regex];
    return [urlTest evaluateWithObject:url];
}

• 用法举例：自定义NSURLProtocol， 决定请求是否需要当前协议对象处理

/**
 决定请求是否需要当前协议对象处理

*/
+(BOOL)canInitWithRequest:(NSURLRequest *)request{
    
    if ([NSURLProtocol propertyForKey:protocolKey inRequest:request]) {
        return NO;
    }
    NSString * url = request.URL.absoluteString;
    return [self isUrl:url];
}

2.5 判断字符串是否为IP地址

/**
 * 判断字符串是否为IP地址
 * param iPAddress IP地址字符串
 * return BOOL 是返回YES，否返回NO
 */
+ (BOOL)isIPAddress:(NSString *)iPAddress{
    NSString *pattern = @"^(\\d{1,2}|1\\d\\d|2[0-4]\\d|25[0-5]).(\\d{1,2}|1\\d\\d|2[0-4]\\d|25[0-5]).(\\d{1,2}|1\\d\\d|2[0-4]\\d|25[0-5]).(\\d{1,2}|1\\d\\d|2[0-4]\\d|25[0-5])$";
    return [self isText:iPAddress pattern:pattern];
    
}

+ (BOOL)isText:(NSString *)text pattern:(NSString *)pattern{
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",pattern];
    return [predicate evaluateWithObject:text];
}

2.6 正则表达式的一些元字符

III 从数组搜索特定条件的元素

从数组中筛选type=8的电子签名数据，避免遍历数组 certificateInfoList