digital
Python3 supports four numeric types: int, float, bool, and complex (plural number)
. Number objects will be created when a variable is assigned. Use the del statement to delete references to some numeric objects.
String
The string cannot be changed Enclose it
with single quotes' or double quotes "and use backslash \ to escape special characters. Add an r before the string, which means that the original string
index value starts at 0 and -1 is from the end The start position of "open left and close right" when intercepting