String formatting output, the while loop, operators.

1. The output string formatting
% placeholder:
declared type of placeholder% s - string% d /% i - escaped become common integer %%%
% () no more, no less, a a correspondence
f "{}" braces are generally put in the content string variable in single quotes
version 3.6 and above to use
2.while cycle
while key conditions: (infinite loop)
loop
condition terminates the loop
break terminates the current cycle
continue out of this cycle, the next cycle to continue to masquerade as the last line of the loop body

1. Operators
   arithmetic operators
   • • • /% ** //
         assignment operator
         + = = - = = * / ** =% = = = //
         logical operators
         and (with - and) or (or) Not (non - not)
         comparison operators
         ! == => <> = <=
         member operator
         in is not in not in
         4 encoding
         ASCII code - does not support Chinese
         GBK - GB:
         English one-byte
         Chinese two-byte
         Unicode - Unicode:
         English 2 bytes
         Chinese 4 bytes
         utf-8 - the most popular encoding
         English one byte
         European two-byte
         Asian 3 bytes
         unit conversion:
         . IB = 8B
         1024B = 1KB
         1024KB 1MB =
         1024MB = 1GB
         1024GB 1TB =
         `` `