我正在嘗試使用 python 用逗號分隔字串：
s = "year:2020,concepts:[ab553,cd779],publisher:elsevier"
但我想忽略括號 [] 中的任何逗號。所以上面的結果是：
["year:2020", "concepts:[ab553,cd779]", "publisher:elsevier"]
有人對如何做到這一點有建議嗎？我嘗試像這樣使用 re.split ：
params = re.split(",(?![\w\d\s])", param)
但它不能正常作業。
uj5u.com熱心網友回復：
此正則運算式適用于您的示例：
,(?=[^,] ?:)
在這里，我們使用正向前瞻來查找逗號，后跟非逗號和冒號字符，然后是冒號。這可以正確找到<comma><key>您正在搜索的模式。當然，如果允許鍵有逗號，則必須進一步調整。
你可以在這里查看正則運算式
uj5u.com熱心網友回復：
result = re.split(r",(?!(?:[^,\[\]] ,)*[^,\[\]] ])", subject, 0)
, # Match the character “,” literally
(?! # Assert that it is impossible to match the regex below starting at this position (negative lookahead)
(?: # Match the regular expression below
[^,\[\]] # Match any single character NOT present in the list below
# The literal character “,”
# The literal character “[”
# The literal character “]”
# Between one and unlimited times, as many times as possible, giving back as needed (greedy)
, # Match the character “,” literally
)
* # Between zero and unlimited times, as many times as possible, giving back as needed (greedy)
[^,\[\]] # Match any single character NOT present in the list below
# The literal character “,”
# The literal character “[”
# The literal character “]”
# Between one and unlimited times, as many times as possible, giving back as needed (greedy)
] # Match the character “]” literally
)
更新以支持括號中的 2 個以上的專案。例如
year:2020,concepts:[ab553,cd779],publisher:elsevier,year:2020,concepts:[ab553,cd779,xx345],publisher:elsevier
uj5u.com熱心網友回復：
您可以使用用戶定義的函式而不是拆分來解決這個問題：
s = "year:2020,concepts:[ab553,cd779],publisher:elsevier"
def split_by_commas(s):
lst = list()
last_bracket = ''
word = ""
for c in s:
if c == '[' or c == ']':
last_bracket = c
if c == ',' and last_bracket == ']':
lst.append(word)
word = ""
continue
elif c == ',' and last_bracket == '[':
word = c
continue
elif c == ',':
lst.append(word)
word = ""
continue
word = c
lst.append(word)
return lst
main_lst = split_by_commas(s)
print(main_lst)
上述代碼運行結果：
['year:2020', 'concepts:[ab553,cd779]', 'publisher:elsevier']
uj5u.com熱心網友回復：
使用僅具有前瞻的模式來斷言右側的字符，如果左側有伴隨字符，則不會斷言。
除了使用拆分之外，您還可以匹配方括號之間的 1 個或多個重復值，或者匹配除逗號之外的任何字符。
(?:[^,]*\[[^][]*]) [^,]*|[^,]
正則運算式演示
s = "year:2020,concepts:[ab553,cd779],publisher:elsevier"
params = re.findall(r"(?:[^,]*\[[^][]*]) [^,]*|[^,] ", s)
print(params)
輸出
['year:2020', 'concepts:[ab553,cd779]', 'publisher:elsevier']
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