最简单的方法来解释字符串:数字，'，‘和'-'？

Question

这是一个有点模糊的标题，但我正在编写一个函数，它执行以下操作：

'1,2,3,4' -> [1,2,3,4]  
'1,2-4'   -> [1,2,3,4]  
'1-3,4'   -> [1,2,3,4]  
'1,1,1'   -> [1]  
'3-9, 1'  -> [1,3,4,5,6,7,8,9]  
'4-1,6'   -> [1,2,3,4,6]  

'，‘表示前一个数字是完整的，并将其添加到列表中。

'-‘表示将所有数字相加，包括在两边的两个数字之间。

应避免空格，并应忽略重复项

我有一些简陋的python代码，可以让您了解我要做的事情：

def seasons_dict(seasons):

    season_dict = {}

    current = ''
    a = ''
    b = ''
    for i in range(len(seasons)):
        if seasons[i].isdigit():
            current = current + seasons[i]
            if (len(seasons) == (i + 1)) and (current not in season_dict):
                if a == '':
                    season_dict[current] = {}
                    current = ''
                else: 
                    b = current
                    if a == b:
                        season_dict[a] = {}
                        current = ''
                    elif b > a:
                        for s in range(int(a), int(b) + 1):
                            season_dict[str(s)] = {}
                        current = ''
                    elif a > b:
                        for s in range(int(b), int(a) + 1):
                            season_dict[str(s)] = {}
                        current = ''
        elif (seasons[i] == ','):
            if (a == '') and (current not in season_dict):
                season_dict[current] = {}
                current = ''
            elif (a != '') and (current not in season_dict):
                b = current
                if a == b:
                    season_dict[a] = {}
                    current = ''
                elif b > a:
                    for s in range(int(a), int(b) + 1):
                        season_dict[str(s)] = {}
                    current = ''
                elif a > b:
                    for s in range(int(b), int(a) + 1):
                        season_dict[str(s)] = {}
                    current = ''
                a = ''
            else:
                current = ''
        elif seasons[i] == '-':
            a = current
            current = ''

    return season_dict  

是的，我知道我最初说的是list，现在我正在处理字典，但这真的没有什么不同。通常来说，列表更容易思考。

提前感谢大家！如果你有任何问题，请告诉我

Answer 1

我认为使用正则表达式来解析你的小迷你语言会让你大大简化代码：

import re

def parse_numbers(num_str):
    results = set()
    for first, second in re.findall(r'(\d+)(?:\s*-\s*(\d+))?', num_str):
        if second:
            if int(first) > int(second):
                first, second = second, first
            results.update(range(int(first), int(second)+1))
        else:
            results.add(int(first)
    return sorted(results)

这可能比您想要的更宽松一些，因为它忽略了不是一个数字或中间有破折号的数字对的任何内容。如果你给它'1,2,foo,3-5'，它会很高兴地解析出[1, 2, 3, 4, 5]，而忽略foo。如果您担心这一点，您可以编写一个单独的正则表达式来验证输入。同时验证和解析有点困难，所以我会在两个单独的过程中完成。

Answer 2

您可以使用集合、排序、解析和范围来执行以下操作：

tests=['1,2,3,4', 
'1,2-4',   
'1-3,4' , 
'1,1,1',   
'3-9, 1',    
'4-1,6',]

for s in tests:
    uniq=set()
    for e in s.split(','):
        if '-' in e:
            t=tuple(map(int, sorted(e.split('-',1))))
            uniq |= set(range(t[0],t[1]+1)) 
        else:
            uniq.add(int(e))
    li=sorted(uniq)

    print("{:10s} -> {}".format(s, li)) 

打印：

1,2,3,4    -> [1, 2, 3, 4]
1,2-4      -> [1, 2, 3, 4]
1-3,4      -> [1, 2, 3, 4]
1,1,1      -> [1]
3-9, 1     -> [1, 3, 4, 5, 6, 7, 8, 9]
4-1,6      -> [1, 2, 3, 4, 6]