8/22 I/O日記

Algorithm

• Python - collections.Counter([iterable]): This is similar to a HashMap and is used for easy counting of elements. Unlike HashMap, it's easier to initialize because Counter returns 0 if the target element is not present, whereas HashMap returns a KeyError. Therefore, sometimes it might be more efficient to use Counter.

  • Example: a = collections.Counter(iterable)

• Character Comparison: These two characters are comparable because Python computes their values based on Unicode points.

  • Example: print('t' > 'a')

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AWS

• Elastic Beanstalk: A service that helps developers build infrastructure much more easily and all at once. For example, it can set up EC2, ELB, Auto Scaling, and RDS simultaneously.

• EBS vs EFS:

  • EBS: Can only be set up in the same Availability Zone (AZ).

  • EFS: Can be set up across multiple AZs.

• Reserved Instance: A long-term contract, such as 3 years, which can save a lot on EC2 costs.

• Spot Instances: The cheapest option for setting up EC2, but it can unpredictably stop due to a shortage of available instances.

• On-Demand: EC2 instances that you can use anytime, but they are more expensive.

• S3: A storage service used for unstructured data types such as images and program files. On the other hand, RDS is better for structured data types like user data and email addresses (i.e., a database). The S3 key name appears to have a directory-like structure, such as dire/dire2/filename, but it is actually just a long name using '/'.

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John the Ripper

• raw-md5: A simple MD5 format.

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Regex

• Regular Expression: Still learning, with the goal of deeply understanding and using it elegantly.