1. 下面一个简单的使用正则表达式的一个例子:NSRegularExpression 类
-(void)parseString{
//组装一个字符串,需要把里面的网址解析出来
NSString *[email protected]"sfdsfhttp://www.baidu.com";
//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
NSError *error;
//http+:[^\\s]* 这个表达式是检测一个网址的。
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"http+:[^\\s]*" options:0 error:&error];
if (regex != nil) {
NSTextCheckingResult *firstMatch=[regex firstMatchInString:urlStringoptions:0range:NSMakeRange(0, [urlString length])];
if (firstMatch) {
NSRange resultRange = [firstMatch rangeAtIndex:0]; //等同于 firstMatch.range --- 相匹配的范围
//从urlString当中截取数据
NSString *result=[urlString substringWithRange:resultRange];
//输出结果
NSLog(@"%@",result);
}
}
}
2.使用正则表达式来判断
//初始化一个NSRegularExpression 对象,并设置检测对象范围为:0-9
NSRegularExpression *regex2 = [NSRegularExpression regularExpressionWithPattern:@"^[0-9]*$" options:0 error:nil];
if (regex2)
{//对象进行匹配
NSTextCheckingResult *result2 = [regex2 firstMatchInString:textField.text options:0 range:NSMakeRange(0, [textField.text length])];
if (result2) {
}
}
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1。 判断邮箱格式是否正确的代码:NSPredicatel类//利用正则表达式验证
NSPredicatel类:主要用来指定过滤器的条件,该对象可以准确的描述所需条件,对每个对象通过谓词进行筛选,判断是否与条件相匹配。谓词是指在计算机中表示计算真假值的函数。原理和用法都类似于SQL查询中的where,作用相当于数据库的过滤取。主要用于从集合中分拣出符合条件的对象,也可以用于字符串的正则匹配
-(BOOL)isValidateEmail:(NSString *)email
{
NSString *emailRegex = @"[A-Z0-9a-z._%+-][email protected][A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES%@",emailRegex];
return [emailTest evaluateWithObject:email];
}
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2 。 匹配9-15个由字母/数字组成的字符串的正则表达式:NSString * regex = @"^[A-Za-z0-9]{9,15}$";
NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];
BOOL isMatch = [pred evaluateWithObject:txtfldPhoneNumber.text];Cocoa用NSPredicate描述查询的方式,原理类似于在数据库中进行查询
用BETWEEN,IN,BEGINWITH,ENDWITH,CONTAINS,LIKE这些谓词来构造NSPredicate,必要的时候使用SELF直接对自己进行匹配
[cpp]
//基本的查询
NSPredicate *predicate;
predicate = [NSPredicate predicateWithFormat: @"name == ‘Herbie‘"];
BOOL match = [predicate evaluateWithObject: car];
NSLog (@"%s", (match) ? "YES" : "NO");
//在整个cars里面循环比较
predicate = [NSPredicate predicateWithFormat: @"engine.horsepower > 150"];
NSArray *cars = [garage cars];
for (Car *car in [garage cars]) {
if ([predicate evaluateWithObject: car]) {
NSLog (@"%@", car.name);
}
}
//输出完整的信息
predicate = [NSPredicate predicateWithFormat: @"engine.horsepower > 150"];
NSArray *results;
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", results);
//含有变量的谓词
NSPredicate *predicateTemplate = [NSPredicate predicateWithFormat:@"name == $NAME"];
NSDictionary *varDict;
varDict = [NSDictionary dictionaryWithObjectsAndKeys:
@"Herbie", @"NAME", nil];
predicate = [predicateTemplate predicateWithSubstitutionVariables: varDict];
NSLog(@"SNORGLE: %@", predicate);
match = [predicate evaluateWithObject: car];
NSLog (@"%s", (match) ? "YES" : "NO");
//注意不能使用$VARIABLE作为路径名,因为它值代表值
//谓词字符窜还支持c语言中一些常用的运算符
predicate = [NSPredicate predicateWithFormat:
@"(engine.horsepower > 50) AND (engine.horsepower < 200)"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"oop %@", results);
predicate = [NSPredicate predicateWithFormat: @"name < ‘Newton‘"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", [results valueForKey: @"name"]);
//强大的数组运算符
predicate = [NSPredicate predicateWithFormat:
@"engine.horsepower BETWEEN { 50, 200 }"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", results);
NSArray *betweens = [NSArray arrayWithObjects:
[NSNumber numberWithInt: 50], [NSNumber numberWithInt: 200], nil];
predicate = [NSPredicate predicateWithFormat: @"engine.horsepower BETWEEN %@", betweens];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", results);
predicateTemplate = [NSPredicate predicateWithFormat: @"engine.horsepower BETWEEN $POWERS"];
varDict = [NSDictionary dictionaryWithObjectsAndKeys: betweens, @"POWERS", nil];
predicate = [predicateTemplate predicateWithSubstitutionVariables: varDict];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", results);
//IN运算符
predicate = [NSPredicate predicateWithFormat: @"name IN { ‘Herbie‘, ‘Snugs‘, ‘Badger‘, ‘Flap‘ }"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", [results valueForKey: @"name"]);
predicate = [NSPredicate predicateWithFormat: @"SELF.name IN { ‘Herbie‘, ‘Snugs‘, ‘Badger‘, ‘Flap‘ }"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", [results valueForKey: @"name"]);
names = [cars valueForKey: @"name"];
predicate = [NSPredicate predicateWithFormat: @"SELF IN { ‘Herbie‘, ‘Snugs‘, ‘Badger‘, ‘Flap‘ }"];
results = [names filteredArrayUsingPredicate: predicate];//这里限制了SELF的范围
NSLog (@"%@", results);
//BEGINSWITH,ENDSWITH,CONTAINS
//附加符号,[c],[d],[cd],c表示不区分大小写,d表示不区分发音字符,cd表示什么都不区分
predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH ‘Bad‘"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", results);
predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH ‘HERB‘"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", results);
predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH[cd] ‘HERB‘"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", results);
//LIKE运算符(通配符)
predicate = [NSPredicate predicateWithFormat: @"name LIKE[cd] ‘*er*‘"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", results);
predicate = [NSPredicate predicateWithFormat: @"name LIKE[cd] ‘???er*‘"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", results);//基本的查询
NSPredicate *predicate;
predicate = [NSPredicate predicateWithFormat: @"name == ‘Herbie‘"];
BOOL match = [predicate evaluateWithObject: car];
NSLog (@"%s", (match) ? "YES" : "NO");
//在整个cars里面循环比较
predicate = [NSPredicate predicateWithFormat: @"engine.horsepower > 150"];
NSArray *cars = [garage cars];
for (Car *car in [garage cars]) {
if ([predicate evaluateWithObject: car]) {
NSLog (@"%@", car.name);
}
}
//输出完整的信息
predicate = [NSPredicate predicateWithFormat: @"engine.horsepower > 150"];
NSArray *results;
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", results);
//含有变量的谓词
NSPredicate *predicateTemplate = [NSPredicate predicateWithFormat:@"name == $NAME"];
NSDictionary *varDict;
varDict = [NSDictionary dictionaryWithObjectsAndKeys:
@"Herbie", @"NAME", nil];
predicate = [predicateTemplate predicateWithSubstitutionVariables: varDict];
NSLog(@"SNORGLE: %@", predicate);
match = [predicate evaluateWithObject: car];
NSLog (@"%s", (match) ? "YES" : "NO");
//注意不能使用$VARIABLE作为路径名,因为它值代表值
//谓词字符窜还支持c语言中一些常用的运算符
predicate = [NSPredicate predicateWithFormat:
@"(engine.horsepower > 50) AND (engine.horsepower < 200)"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"oop %@", results);
predicate = [NSPredicate predicateWithFormat: @"name < ‘Newton‘"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", [results valueForKey: @"name"]);
//强大的数组运算符
predicate = [NSPredicate predicateWithFormat:
@"engine.horsepower BETWEEN { 50, 200 }"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", results);
NSArray *betweens = [NSArray arrayWithObjects:
[NSNumber numberWithInt: 50], [NSNumber numberWithInt: 200], nil];
predicate = [NSPredicate predicateWithFormat: @"engine.horsepower BETWEEN %@", betweens];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", results);
predicateTemplate = [NSPredicate predicateWithFormat: @"engine.horsepower BETWEEN $POWERS"];
varDict = [NSDictionary dictionaryWithObjectsAndKeys: betweens, @"POWERS", nil];
predicate = [predicateTemplate predicateWithSubstitutionVariables: varDict];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", results);
//IN运算符
predicate = [NSPredicate predicateWithFormat: @"name IN { ‘Herbie‘, ‘Snugs‘, ‘Badger‘, ‘Flap‘ }"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", [results valueForKey: @"name"]);
predicate = [NSPredicate predicateWithFormat: @"SELF.name IN { ‘Herbie‘, ‘Snugs‘, ‘Badger‘, ‘Flap‘ }"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", [results valueForKey: @"name"]);
names = [cars valueForKey: @"name"];
predicate = [NSPredicate predicateWithFormat: @"SELF IN { ‘Herbie‘, ‘Snugs‘, ‘Badger‘, ‘Flap‘ }"];
results = [names filteredArrayUsingPredicate: predicate];//这里限制了SELF的范围
NSLog (@"%@", results);
//BEGINSWITH,ENDSWITH,CONTAINS
//附加符号,[c],[d],[cd],c表示不区分大小写,d表示不区分发音字符,cd表示什么都不区分
predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH ‘Bad‘"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", results);
predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH ‘HERB‘"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", results);
predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH[cd] ‘HERB‘"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", results);
//LIKE运算符(通配符)
predicate = [NSPredicate predicateWithFormat: @"name LIKE[cd] ‘*er*‘"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", results);
predicate = [NSPredicate predicateWithFormat: @"name LIKE[cd] ‘???er*‘"];
results = [cars filteredArrayUsingPredicate: predicate];
NSLog (@"%@", results);