The error AttributeError: 'NoneType' object has no attribute 'group' occurs because the match function did not find a match and returned None. When you try to call group on None, it raises an AttributeError. To fix this, you should first check if a match was found before trying to access the groups. Here's how you can do it: import re pattern = re.compile(r'(\d{4})-(\d{2})-(\d{2})') match = pattern.match('2024-06-16') if match: print(match.group(1)) else: print("No match found.") This way, you handle the case where no match is found and avoid the AttributeError.

import re

pattern = re.compile(r'(\d{4})-(\d{2})-(\d{2})')
match = pattern.match('2024-06-16')

if match:
    print(match.group(1))
else:
    print("No match found.")

Here's how you can check the exit status of gcc: #!/bin/bash # Run the gcc command gcc "$2".c -Wall -g -o "$2" > "$1" 2>&1 # Get the exit status of gcc status=$? # Output the appropriate message based on the exit status if [ $status -eq 0 ]; then echo "compile V" else echo "compile X" fi # Return the exit status of gcc exit $status

#!/bin/bash

# Run the gcc command
gcc "$2".c -Wall -g -o "$2" > "$1" 2>&1

# Get the exit status of gcc
status=$?

# Output the appropriate message based on the exit status
if [ $status -eq 0 ]; then
  echo "compile V"
else
  echo "compile X"
fi

# Return the exit status of gcc
exit $status

There are several approaches to handle authentication in a React Native app, but one common method is to use JSON Web Tokens (JWT). Here's a basic example of how you can implement JWT authentication in your React Native app: User Login: When a user logs in, send their credentials to the server. If the credentials are correct, the server generates a JWT token and sends it back to the client. Token Storage: Store the JWT token securely on the client-side (e.g., in AsyncStorage or SecureStore). Protected Routes: For protected routes, include the JWT token in the request header. The server verifies the token and grants access if it's valid. Token Expiry: Set an expiration time for the JWT token to improve security. Users will need to reauthenticate once the token expires. Here's a basic implementation using AsyncStorage for token storage: // Login Screen const login = async (username, password) => { try { const response = await fetch('https://your-api.com/login', { method: 'POST', headeRead more

// Login Screen
const login = async (username, password) => {
  try {
    const response = await fetch('https://your-api.com/login', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({ username, password }),
    });

    const { token } = await response.json();
    await AsyncStorage.setItem('token', token);
  } catch (error) {
    console.error(error);
  }
};

// Protected Route
const getProtectedData = async () => {
  try {
    const token = await AsyncStorage.getItem('token');
    const response = await fetch('https://your-api.com/protected-data', {
      method: 'GET',
      headers: {
        'Authorization': `Bearer ${token}`,
        'Content-Type': 'application/json',
      },
    });

    const data = await response.json();
    return data;
  } catch (error) {
    console.error(error);
  }
};