[英]Find and count instance of substring within multiple strings using python
我在 python 中有一個帶有多個子查詢的 sql 查詢。 所以設置是一個較大字符串中的多個子字符串。 我想檢查子字符串中字符串的實例數。 比我所看到的更多參與並感謝您的幫助。
像這樣設置 -
qry = '''
with
qry_1 as (
SELECT ID,
NAME
FROM ( ... other code...
),
qry_2 as (
SELECT coalesce (table1.ID, table2.ID) as ID,
NAME
FROM (...other code...
),
qry_3 as (
SELECT id.WEATHER AS WEATHER_MORN,
ROW_NUMBER() OVER(PARTITION BY id.SUN
ORDER BY id.TIME) AS SUN_TIME,
id.RAIN,
id.MIST
FROM (...other code..
)
'''
我想計算qry_1, qry_2, qry_3
內的ID
實例。
我認為會利用re.findall
和 substring 搜索?
re.findall(r'as \( select (.+?) from \(',qry)
然后在其中查找和計算ID
實例? output 是 2。但我不確定如何......
您可以拆分 CTE 查詢,然后在子查詢的截斷版本上使用re.findall
:
qry = '''
with
qry_1 as (
SELECT ID,
NAME
FROM ( ... other code...
),
qry_2 as (
SELECT coalesce (table1.ID, table2.ID) as ID,
NAME
FROM (...other code...
),
qry_3 as (
SELECT WEATHER
FROM (...other code..
)
'''
def get_cols(s):
[cte_name] = re.findall('^\w+(?=\sas)|(?<=with\s)\w+(?=\sas)', s)
cols = re.findall('(?<=as\s)[\w\.]+|(?<=SELECT\s)[\w\.]+|(?<=,\s)[\w\.]+', s)
return [cte_name, cols]
#dictionary with the cte name as the key, and the columns as the values
v = dict(get_cols(re.sub('coalesce\s\(.+\)|[\s\n]+', ' ', i)) for i in re.split('(?<=\)),(?:\s+)*\n', qry))
#filter the dictionary above to only include desired column names
r = {a:k if (k:=[i for i in b if i in {'NAME', 'ID'}]) else None for a, b in v.items()}
Output:
{'qry_1': ['ID', 'NAME'], 'qry_2': ['ID', 'NAME'], 'qry_3': None}
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