With the popularity of the Internet and smart phones, phone numbers have become a very important piece of information. For many websites and applications, they need to verify that the phone number entered by the user conforms to a standard format. And this is where regular expressions come in. In this article, we will discuss how to use PHP's regular expressions to verify whether the input string is the correct mobile phone number, landline number, or 400 phone number.
1. Verify mobile phone number
First let’s look at how to verify mobile phone number. In China, mobile phone numbers usually consist of 11 digits starting with 1 (such as 13700000000). The regular expression for verifying mobile phone numbers is as follows:
/^1[3-9]d{9}$/
Next, let’s explain this regular expression. First, it must start with the number 1, then any number between 3 and 9 (this is to exclude mobile phone numbers starting with 10, 11, and 12), and then it must be followed by 9 numbers. The final $ represents the end of the string.
The following is a complete PHP function for verifying mobile phone numbers:
function isMobile($mobile) { return preg_match('/^1[3-9]d{9}$/', $mobile); }
Using this function, we can easily verify whether the entered mobile phone number conforms to the standard format:
if (isMobile('13700000000')) { echo '手机号码格式正确'; } else { echo '手机号码格式不正确'; }
2. Verify landline numbers
As for landline numbers, they usually consist of two parts: area code and fixed phone number. For example, 010-12345678 is a landline number. The regular expression to verify the landline number is as follows:
/^(0d{2,3}-)?d{7,8}$/
Next, let’s explain this regular expression. First, the string can contain an area code portion. The format of the area code must start with 0, followed by 2 to 3 digits, and use a - sign as a separator. Without the area code, the entire string is just 7 to 8 digits.
The following is a complete PHP function for validating landline numbers:
function isTelephone($telephone) { return preg_match('/^(0d{2,3}-)?d{7,8}$/', $telephone); }
Using this function, we can easily verify whether the entered landline number conforms to the standard format:
if (isTelephone('010-1234567')) { echo '座机号码格式正确'; } else { echo '座机号码格式不正确'; }
3. Verify the 400 phone number
Finally, let’s look at how to verify the 400 phone number. In China, the 400 number usually consists of 10 digits (such as 400-123-4567). The regular expression to verify the 400 phone number is as follows:
/^400(-d{3,4}){2}$/
Next, let’s explain this regular expression. First, the string starts with 400, which must be followed by 2 groups of 3 to 4 digits separated by - signs.
The following is a complete PHP function for verifying the 400 phone number:
function is400($number) { return preg_match('/^400(-d{3,4}){2}$/', $number); }
Using this function, we can easily verify whether the entered 400 phone number conforms to the standard format:
if (is400('400-123-4567')) { echo '400电话号码格式正确'; } else { echo '400电话号码格式不正确'; }
To sum up, we can easily verify whether the input string is the correct mobile phone number, landline number or 400 phone number through regular expressions. Doing this helps us ensure the correctness of the phone number and also improves the user experience of the application.
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