- lexical-analysis.py
- lexical-analysis.py
#!# ==================
#!# Lexical Analysis
#!# ==================
#!#
#!# This page contains a memo on lexical analysis.
#!#
#!# For a complete reference documentation, look at https://docs.python.org/3.6/reference/lexical_analysis.html
#!#
#!# Python Keywords
#!# ---------------
#!#
#!# .. code-block:: py3
#!#
#!# False class finally is return
#!# None continue for lambda try
#!# True def from nonlocal while
#!# and del global not with
#!# as elif if or yield
#!# assert else import pass
#!# break except in raise
#!#
#!# Reserved classes of identifiers
#!# -------------------------------
#!#
#!# :code:`_*`
#!# Not imported by from module import *
#!# :code:`__*__`
#!# System-defined names
#!# :code:`__*`
#!# Class-private names
#!#
#!# Usually, :code:`_` is assigned to last evaluation or used in conjunction with *gettext* for internationalization.
#!#
#!# Indentation
#!# -----------
#!# Using continuation, backslash character "\\":
def check_date(year, month, day, hour, minute, second):
if 1900 < year < 2100 and 1 <= month <= 12 \
and 1 <= day <= 31 and 0 <= hour < 24 \
and 0 <= minute < 60 and 0 <= second < 60:
return True
#!# Better, using parenthesis, brace and bracket:
def check_date(year, month, day, hour, minute, second):
if (1900 < year < 2100 and 1 <= month <= 12
and 1 <= day <= 31 and 0 <= hour < 24
and 0 <= minute < 60 and 0 <= second < 60):
return True
x = (1 +
2 * 3 -
4 / 6)
3.3.10. Lexical Analysis¶
This page contains a memo on lexical analysis.
For a complete reference documentation, look at https://docs.python.org/3.6/reference/lexical_analysis.html
3.3.10.1. Python Keywords¶
False class finally is return
None continue for lambda try
True def from nonlocal while
and del global not with
as elif if or yield
assert else import pass
break except in raise
3.3.10.2. Reserved classes of identifiers¶
_*- Not imported by from module import *
__*__- System-defined names
__*- Class-private names
Usually, _ is assigned to last evaluation or used in conjunction with gettext for internationalization.
3.3.10.3. Indentation¶
Using continuation, backslash character “":
def check_date(year, month, day, hour, minute, second):
if 1900 < year < 2100 and 1 <= month <= 12 \
and 1 <= day <= 31 and 0 <= hour < 24 \
and 0 <= minute < 60 and 0 <= second < 60:
return True
Better, using parenthesis, brace and bracket:
def check_date(year, month, day, hour, minute, second):
if (1900 < year < 2100 and 1 <= month <= 12
and 1 <= day <= 31 and 0 <= hour < 24
and 0 <= minute < 60 and 0 <= second < 60):
return True
x = (1 +
2 * 3 -
4 / 6)