python - 多行搜索和替换

我有一个非结构化文件，我想搜索和替换字符串模式。
必须替换在String和String之间存在的字符串；该模式之外的字符串应该保持原样。
文件格式如下

col4 is required to be upper so
make col4 upper
abc 12345 !$% DATA SELECT
col1 as col1,
col2 as col2.
col3,
sch.col4 as col4,
sch.tab.col4 as col4_1,
col4,
col5 FROM sch.tab
xyz 34354 ^&* DATA SELECT
col5 as col5,
col3,
col4,
col4 as col4,
col4 FROM
blah blah blah

我想替换：
col4,和upper(col4) as col4,
sch.col4和upper(sch.col4)
sch.tab.col4和upper(sch.tab.col4)
col4（如果col4位于select查询的末尾）使用upper(col4) as col4
该文件在Linux服务器上，我尝试使用sed和awk缩小包含col4的行，但无法从那里向前移动。
我能用下面的方法识别出一种模式

awk '/SELECT/,/FROM/' test_file.txt | awk '/col4/{print $0, NR}' | awk -F AS '{print $1}'

查找“选择”和“来自”之间的文本
找出有COL4的线路
打印第一个字段

sed -n -e '/SELECT/,/FROM/p' -e 's/\(\([a-zA-Z]\{1,\}\.\)\{0,\}\)col4/upper(\0)/g' test_file.txt

使用sed
实际：

col4 is required to be upper so
make col4 upper
abc 12345 !$% DATA SELECT
col1 as col1,
col2 as col2.
col3,
sch.col4 as col4,
sch.tab.col4 as col4_1,
col4,
col5 FROM sch.tab
xyz 34354 ^&* DATA SELECT
col5 as col5,
col3,
col4,
col4 as col4,
col4 FROM
blah blah blah

预期结果：

col4 is required to be upper so
make col4 upper
abc 12345 !$% DATA SELECT
col1 as col1,
col2 as col2.
col3,
upper(sch.col4) as col4,
upper(sch.tab.col4) as col4_1,
upper(col4) as col4,
col5 FROM sch.tab
xyz 34354 ^& DATA SELECT
col5 as col5,
col3,
upper(col4) as col4,
upper(col4) as col4,
upper(col4) as col4 FROM
blah blah blah

非常感谢您的帮助！啊！

最佳答案

我认为，至少95%的人这样做了。如果有错误，请告诉我：

with open('ej.txt', 'r') as file:
    string=file.read().replace('\n',' ')


import re

matches=re.findall(r'SELECT.*?FROM',string)
replacements={"col4,":"upper(col4) as col4,",
             "sch.col4":"upper(sch.col4)",
             "sch.tab.col4":"upper(sch.tab.col4)",
             "col4 as col4,": "upper(col4) as col4,"}
new_matches=[]
for match in matches:
    for k,v in replacements.items():
        match=match.replace(k,v)
    new_matches.append(match)


for k,v in {k:v for k,v in zip(matches,new_matches)}.items() :
    string=string.replace(k,v)

string

关于python - 多行搜索和替换，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/56189622/

Col4

python - 多行搜索和替换