Convert a string to a list

[rh0dium]

Hi all,

I am using pexpect to drive another tool. Some of the data I get back
would be better suited as a list and I want to know a simple way to
parse the data to push it into a list.

For example

I get the following string back. I want to convert this to a list:

'("." ".." "cdslib_cleanup.py" "cadence.py"
"cdsinit_cdsenv_cleanup.py")'

should be:
["." ".." "cdslib_cleanup.py" "cadence.py"
"cdsinit_cdsenv_cleanup.py"]

It should be able to handle embeded lists like this:
'("." ("cadence.py" "foo_cleanup.py") "cdslib_cleanup.py" "cadence.py"
"cdsinit_cdsenv_cleanup.py")'

should become
["." ["cadence.py" "foo_cleanup.py"] "cdslib_cleanup.py" "cadence.py"
"cdsinit_cdsenv_cleanup.py"]

Is there some exisitng code which will handle this task?

 

[Nick Craig-Wood]

I am using pexpect to drive another tool. Some of the data I get back
would be better suited as a list and I want to know a simple way to
parse the data to push it into a list.

For example

I get the following string back. I want to convert this to a list:

'("." ".." "cdslib_cleanup.py" "cadence.py"
"cdsinit_cdsenv_cleanup.py")'

should be:
["." ".." "cdslib_cleanup.py" "cadence.py"
"cdsinit_cdsenv_cleanup.py"]

It should be able to handle embeded lists like this:
'("." ("cadence.py" "foo_cleanup.py") "cdslib_cleanup.py" "cadence.py"
"cdsinit_cdsenv_cleanup.py")'

should become
["." ["cadence.py" "foo_cleanup.py"] "cdslib_cleanup.py" "cadence.py"
"cdsinit_cdsenv_cleanup.py"]

Here is a cheap, nasty and insecure solution

It made tuples rather than lists but I expect that won't matter.

Someone normally chimes in with pyparsing at this point...

 

[Paul McGuire]

Someone normally chimes in with pyparsing at this point...

Well it *is* a short pyparsing routine, after all...

-- Someone


tests = """\
("." ".." "cdslib_cleanup.py" "cadence.py"
"cdsinit_cdsenv_cleanup.py")
("." ("cadence.py" "foo_cleanup.py") "cdslib_cleanup.py" "cadence.py"
"cdsinit_cdsenv_cleanup.py") """.splitlines()

import pyparsing as pp

LPAR,RPAR = map(pp.Suppress,"()")
list_ = pp.Forward()
list_ << ( LPAR +
pp.ZeroOrMore( pp.quotedString | pp.Group(list_) ) +
RPAR )

for t in tests:
result = list_.parseString(t)
print result.asList()

Prints:
['"."', '".."', '"cdslib_cleanup.py"', '"cadence.py"',
'"cdsinit_cdsenv_cleanup.py"']
['"."', ['"cadence.py"', '"foo_cleanup.py"'], '"cdslib_cleanup.py"',
'"cadence.py"', '"cdsinit_cdsenv_cleanup.py"']

 

[Paul McGuire]

Someone normally chimes in with pyparsing at this point...

Well it *is* a short pyparsing routine, after all...

-- Someone

tests = """\
("." ".." "cdslib_cleanup.py" "cadence.py"
"cdsinit_cdsenv_cleanup.py")
("." ("cadence.py" "foo_cleanup.py") "cdslib_cleanup.py" "cadence.py"
"cdsinit_cdsenv_cleanup.py") """.splitlines()

import pyparsing as pp

LPAR,RPAR = map(pp.Suppress,"()")
list_ = pp.Forward()
list_ << ( LPAR +
pp.ZeroOrMore( pp.quotedString | pp.Group(list_) ) +
RPAR )

for t in tests:
result = list_.parseString(t)
print result.asList()

Prints:
['"."', '".."', '"cdslib_cleanup.py"', '"cadence.py"',
'"cdsinit_cdsenv_cleanup.py"']
['"."', ['"cadence.py"', '"foo_cleanup.py"'], '"cdslib_cleanup.py"',
'"cadence.py"', '"cdsinit_cdsenv_cleanup.py"']

Oh, you probably don't want those quotation marks in the parsed
strings. Change:

pp.ZeroOrMore( pp.quotedString | pp.Group(list_) ) +
to:


pp.ZeroOrMore( pp.quotedString.setParseAction(pp.removeQuotes) |
pp.Group(list_) ) +


-- Paul