The reason for the error is NameResolutionError(self.host,self,e)frome, which is an exception type in the urllib3 library. The reason for this error is that DNS resolution failed, that is, the host name or IP address attempted to be resolved cannot be found. This may be caused by the entered URL address being incorrect or the DNS server being temporarily unavailable. How to solve this error There may be several ways to solve this error: Check whether the entered URL address is correct and make sure it is accessible Make sure the DNS server is available, you can try using the "ping" command on the command line to test whether the DNS server is available Try accessing the website using the IP address instead of the hostname if behind a proxy

Differences: 1. Different definitions, url is a uniform resource locator, and html is a hypertext markup language; 2. There can be many urls in an html, but only one html page can exist in a url; 3. html refers to is a web page, and url refers to the website address.

PHP regular expression verification: Number format detection When writing PHP programs, it is often necessary to verify the data entered by the user. One of the common verifications is to check whether the data conforms to the specified number format. In PHP, you can use regular expressions to achieve this kind of validation. This article will introduce how to use PHP regular expressions to verify number formats and provide specific code examples. First, let’s look at common number format validation requirements: Integers: only contain numbers 0-9, can start with a plus or minus sign, and do not contain decimal points. floating point

In Go, you can use regular expressions to match timestamps: compile a regular expression string, such as the one used to match ISO8601 timestamps: ^\d{4}-\d{2}-\d{2}T \d{2}:\d{2}:\d{2}(\.\d+)?(Z|[+-][0-9]{2}:[0-9]{2})$ . Use the regexp.MatchString function to check if a string matches a regular expression.

To validate email addresses in Golang using regular expressions, follow these steps: Use regexp.MustCompile to create a regular expression pattern that matches valid email address formats. Use the MatchString function to check whether a string matches a pattern. This pattern covers most valid email address formats, including: Local usernames can contain letters, numbers, and special characters: !.#$%&'*+/=?^_{|}~-`Domain names must contain at least One letter, followed by letters, numbers, or hyphens. The top-level domain (TLD) cannot be longer than 63 characters.

The method of using regular expressions to verify passwords in Go is as follows: Define a regular expression pattern that meets the minimum password requirements: at least 8 characters, including lowercase letters, uppercase letters, numbers, and special characters. Compile regular expression patterns using the MustCompile function from the regexp package. Use the MatchString method to test whether the input string matches a regular expression pattern.

PHP is a widely used programming language, especially popular in the field of web development. In the process of web development, we often encounter the need to filter and verify text input by users, among which character filtering is a very important operation. This article will introduce how to use regular expressions in PHP to implement Chinese character filtering, and give specific code examples. First of all, we need to clarify that the Unicode range of Chinese characters is from u4e00 to u9fa5, that is, all Chinese characters are in this range.

Regular expressions in Go provide a powerful string processing tool: use the regexp package for regular expression operations. Use regular expression syntax to match and manipulate strings. Matches character classes, repeating characters, groupings, anchors, and boundaries. Match strings with MatchString, extract matches with FindStringSubmatch, and replace strings with ReplaceAllString. Application scenarios include verifying email addresses, extracting HTML links, etc.