Question

I am trying to search and replace all occurrences of __field(unsigned int, a_b) with ctf_integer(unsigned int, a_b, a_b).

Here the text a_b can change with different values.

I tried using regex like this:

m = re.search(r"__field\(unsigned int(.*)\)", string)

But in the result I get two groups and I am unable to understand why. I want to include the possibility to have spaces in it, so I used the wild-card detector .*. Is this a correct way of doing search and replace?

I also tried with \w+, but it does not accomodate for spaces.

The following also does not work if there are no spaces before comma:

m = re.search(r"__field\(unsigned int(\s+),(.*)\)", string)

questions:

why does \s+ option cannot detect zero spaces? any alternatives?
the search returns two groups instead of one, the first spans entire string while the second is after the comma. why is it so?

I can use re.sub as below:

re.sub(r"__field\(unsigned int(\s*),(.*)\)", r"ctf_integer(unsigned int, \2, \2)", string)

However this has a problem if there are multiple closing brackets. For example it doesn't work if the input is A(__field(unsigned int, a_b, a_b)), like so:

string = "A(__field(unsigned int, a_b, a_b))"
re.sub(r"__field\(unsigned int(\s*),(.*)\)", r"ctf_integer(unsigned int, \2, \2)", string)

# Outputs 'A(ctf_integer(unsigned int,  a_b, a_b),  a_b, a_b))'

P.S.: It is being used to convert tracepoints from one format to another.

Answer 1

您应该查找除.*以外的所有内容（)），[^)]*。看起来像这样：

import re
string = "A(__field(unsigned int, a_b, a_b))"
re.sub(r"__field\(unsigned int,\s*([^)]*)\)", r"ctf_integer(unsigned int, \1)", string)

输出：

A(ctf_integer(unsigned int, a_b, a_b))

在上面的代码中，我还删除了捕获空格（将(\s*)更改为\s*），只将一个组编号为\1。此外，我将空格检测移到逗号之后，因为它可能应该是它。

python search and replace with spaces, brackets and underscores

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