Python learning the first part of the fourth day

1, the characteristics of the dictionary: disorderly, go heavy, query faster, more than the list of memory.
2, the dictionary query Speed fast reason: because he is a hash type.
3, what is (hash) hash?

A hash maps a binary of any length to a shorter fixed-length binary, which is called a hash value for a shorter binary value. A hash value is a unique and compact numeric representation of a piece of data. A clear text only the hash values generated under the same process will be the same, and the hash values generated by different processes in plaintext are different.

4, character encoding:

Code under Python2:

Python2 default encoding is ASCII code

The encoding declaration at the beginning of the file is to tell the code that the program reads the code into memory in what encoding format.

Python learning the first part of the fourth day