python - Python 3 中的正则表达式 : match everything after a number or optional period but before an optional comma

Question

我试图在没有任何测量值或说明的情况下退回食谱中的成分。成分列表如下所示:

['1  medium tomato, cut into 8 wedges',
 '4  c. torn mixed salad greens',
 '1/2  small red onion, sliced and separated into rings',
 '1/4  small cucumber, sliced',
 '1/4  c. sliced pitted ripe olives',
 '2  Tbsp. reduced-calorie Italian salad dressing',
 '2  Tbsp. lemon juice',
 '1  Tbsp. water',
 '1/2  tsp. dried mint, crushed',
 '1/4  c. crumbled Feta cheese or 2 Tbsp. crumbled Blue cheese']

我想返回以下列表:

['medium tomato',
 'torn mixed salad greens',
 'small red onion',
 'small cucumber',
 'sliced pitted ripe olives',
 'reduced-calorie Italian salad dressing',
 'lemon juice',
 'water',
 'dried mint',
 'crumbled Blue cheese']

我发现的最接近的模式是:

pattern = '[\s\d\.]* ([^\,]+).*'

但在测试中:

for ing in ingredients:
    print(re.findall(pattern, ing))

每个测量缩写后的句点也被返回，例如:

['c. torn mixed salad greens']

同时

pattern = '(?<=\. )[^.]*$'

无法捕获没有句点的实例，如果两者都出现则捕获逗号，即:

[]
['torn mixed salad greens']
[]
[]
['sliced pitted ripe olives']
['reduced-calorie Italian salad dressing']
['lemon juice']
['water']
['dried mint, crushed']
['crumbled Blue cheese']

提前致谢!

Answer 1

你可以使用这个模式:

for ing in ingredients:
    print(re.search(r'[a-z][^.,]*(?![^,])(?i)', ing).group())

图案细节:

([a-z][^.,]*) # a substring that starts with a letter and that doesn't contain a period
                # or a comma
(?![^,]) # not followed by a character that is not a comma
         # (in other words, followed by a comma or the end of the string)
(?i)     # make the pattern case insensitive