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En este tutorial, aprenderás sobre palabras clave (palabras reservadas en Python) e identificador (nombres de variables, funciones, etc.).
Las palabras clave son palabras reservadas en Python.
No podemos usar palabras clave como nombre de variable,funciónnombres o cualquier otro identificador. Se utilizan para definir la sintaxis y estructura del lenguaje Python.
En Python, las palabras clave distinguen entre mayúsculas y minúsculas.
Python 3.7contiene 33 palabras clave. Este número puede cambiar ligeramente en un período de tiempo.
Todas las palabras clave deben estar en minúsculas, excepto True, False y None. A continuación, se muestra una lista completa de todas las palabras clave.
False | await | else | import | pass |
None | break | except | in | raise |
True | class | finally | is | return |
and | continue | for | lambda | try |
as | def | from | nonlocal | while |
assert | del | global | not | with |
async | elif | if | or | yield |
It may be difficult to view all keywords at once and try to understand their meanings.
If you want to view the list of all keywords, here isall keywordscompletelistand examples.
Identifiers are the names given to entities such as classes, functions, and variables. They help distinguish one entity from another.
Identifiers can be lowercase letters(a to z)or uppercase letter(A to Z)or number(0 to 9)or the combination of underscore (_). myClass, var_1,var_name_1, print_this_to_screen are valid.
Identifiers cannot start with numbers.1is invalid, but variable1 is valid.
cannot be used as identifiers.
>>> global = 1 File "<interactive input>", line 1 global = 1 ^ SyntaxError: invalid syntax
We cannot use keywords like!。,@,#,$,%and such special symbols.
>>> a@ = 0 File "<interactive input>", line 1 a@ = 0 ^ SyntaxError: invalid syntax
Identifiers can be of any length.
Python is Case sensitive language. This means that Variable and variable are two different variables. Also, it is recommended that meaningful identifiers be used in actual programming.
Although, c = 10 is also valid. However, it is recommended to use count = 10 It will be more meaningful, and it will be easier to understand its function and meaning even if you look at the code after a long period of time.
You can use underscores to separate multiple words for naming, for example: this_is_a_long_variable