代码结构

Table of Contents

分支

• 最小化嵌套
• 正向优先

最小化嵌套

提前退出, 优先解决简单问题

# 判断年份是否是闰年 (year % 4 == 0, year % 100 != 0, year % 400 == 0)
def is_leap(year: int) -> bool:
    if year % 4 == 0:
        if year % 100 != 0:
            if year % 400 == 0:
                return True
            else:
                return False
        else:
            return False
    else:
        return False

# 提前退出, 最少条件判断
def is_leap(year: int) -> bool:
    if year % 400 == 0:
        return True

    if year % 100 == 0:
        return False

    if year % 4 == 0:
        return True

    return False

正向优先

正向结果优先

if is_pass:
    # case PASS ...
else:
    # case FAIL ...

if not is_pass:
    # case FAIL ...
else:
    # case PASS ...

if is_fail:
    # case FAIL ...
else:
    # case PASS ...

分支参数, 左边为变量, 右边为常量

 if num > 5:
    pass

边界

简化边界问题, 忽略或合并不关注的内容

array = [1, 2, 3, 4, 5]

if type(index) is int:
    if index >= (-1 * len(array)):
        if index < len(array):
            return array[index]
        else:
            return f"{index} bigger than array length"
    else:
        return f'{index} less than 0'
else:
    return f'{index} is not int'

# 合并 index error 的多种情况
try:
    return array[index]
except IndexError as e:
    return f'{index} error: {e}'

变量的逻辑

• 少创建无效变量
• 减小变量作用域

少创建无效变量

变量越多负担越重
消除无效的中间变量

note = 'Continue the test when error occurred? (default: Y  N/Y)'
input_raw = input(note)
input_no_space = input_raw.strip()
input_up = input_no_space.upper()
input_ok = input_up in ('Y', 'N', '')

if input_up in ('Y', ''):
    print('continue test when error occurred')
else:
    print('stop test when error occurred')


note = 'Continue the test when error occurred? (default: Y  N/Y)'
if input(note).strip().upper() in ('', 'Y'):
    print('continue test when error occurred')
else:
    print('stop test when error occurred')

减小变量作用域

缩减变量作用域以减轻变量的追踪难度
减小变量的使用跨度, 变量定义尽量与使用位置接近

username = 'admin'
password = 'admin'
config = {}
config_valid = {}
tool_dir = 'tools'
log_dir = 'reports/process.log'
count = 0
key = None
value = None


# read config module
config = {}
config_valid = {}

# set output module
log_dir = 'reports/process.log'

# client module
username = 'admin'
password = 'admin'
tool_dir = 'tools'
count = 0