python basis - variable
variable:
1, a variable is a letter or symbol, the value of the generated program is running record, the latter supplying the program to use.
2, variable: the result of the operation of
3, variable, depending on the amount of meaning too can be changed, can also be considered to be our mathematics was unknown x.
For example: a = 3 * 6 left // Note the equal sign in mathematics is not the equal right of meaning, the meaning of the equal sign is the assignment of meaning. The value assigned to the variable right-hand side of the equal sign on the left.
4. "#" comment, followed by the pound sign is a comment, the posters are not for the machine to read. This is called single-line comments.
Multi-line comments: '' '
Exercise:
Note:
A = 18 is
Print ( "A") // output here is a, because it is a string, the string variable does not matter. Another point, there must be a variable to use.
Variable naming conventions:
1, must be a number, letter, underscore combination.
Such as: = "Alex" // _ here is variable
Print ( ) prints out variables //
2, is not purely digital not begin with a digit.
3, remember! Remember! Remember! Variables which must not have Chinese.
4, can not use keywords, which is already occupied by a python stuff.
5, should not be too long.
6, to be meaningful.
7, case-sensitive, and Chinese characters.
8, recommended hump, for example: JingYi. Recommended underline clearly distinguish between each word, such as: jing_yi
constant:
1, there is no absolute constants in python agreement aging, all capital letters is a constant
example: PI = 3.1415926
2, is in fact a constant variable, but usually Xia Buqu change.
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