python sorting negative and/or decimal alphanumeric strings

Question

I'm having problems sorting a list of strings that contain negative and/or decimal alphanumeric strings. This is what I have so far:

import re

format_ids = ["synopsys_SS_2v_-40c_SS.lib",
              "synopsys_SS_1v_-40c_SS.lib",
              "synopsys_SS_1.2v_-40c_SS.lib", 
              "synopsys_SS_1.4v_-40c_SS.lib",
              "synopsys_SS_2v_-40c_TT.lib",
              "synopsys_FF_3v_25c_FF.lib",
              "synopsys_TT_4v_125c_TT.lib",
              "synopsys_TT_1v_85c_TT.lib",
              "synopsys_TT_10v_85c_TT.lib",
              "synopsys_FF_3v_-40c_SS.lib",
              "synopsys_FF_3v_-40c_TT.lib"]

selector = r'.*(FF|TT|SS)_([-\.\d]+v)_([-\.\d]+c)_(FF|TT|SS).*'
#key = [2,1,3]
key = 2
produce_groups = False

if isinstance(key, int):
    key = [key]

convert = lambda text: float(text) if text.isdigit() else text
alphanum_key = lambda k: [convert(c) for c in re.split('([-.\d]+)', k)]
split_list = lambda name: tuple(alphanum_key(re.findall(selector,name)[0][i]) for i in key)
format_ids.sort(key=split_list)

print "\n".join(format_ids)

I'm expecting the following output (sorting by the 3rd key):

synopsys_SS_2v_-40c_SS.lib
synopsys_SS_1v_-40c_SS.lib
synopsys_SS_1.2v_-40c_SS.lib
synopsys_SS_1.4v_-40c_SS.lib
synopsys_SS_2v_-40c_TT.lib
synopsys_FF_3v_-40c_SS.lib
synopsys_FF_3v_-40c_TT.lib
synopsys_FF_3v_25c_FF.lib
synopsys_TT_1v_85c_TT.lib
synopsys_TT_10v_85c_TT.lib
synopsys_TT_4v_125c_TT.lib

But I'm getting the following (all the negative numbers are listed last):

synopsys_FF_3v_25c_FF.lib
synopsys_TT_1v_85c_TT.lib
synopsys_TT_10v_85c_TT.lib
synopsys_TT_4v_125c_TT.lib
synopsys_SS_2v_-40c_SS.lib
synopsys_SS_1v_-40c_SS.lib
synopsys_SS_1.2v_-40c_SS.lib
synopsys_SS_1.4v_-40c_SS.lib
synopsys_SS_2v_-40c_TT.lib
synopsys_FF_3v_-40c_SS.lib
synopsys_FF_3v_-40c_TT.lib

Now, for the decimals from the 2nd key (changing key variable to 1 (key=1)), I get:

synopsys_SS_1v_-40c_SS.lib
synopsys_TT_1v_85c_TT.lib
synopsys_SS_2v_-40c_SS.lib
synopsys_SS_2v_-40c_TT.lib
synopsys_FF_3v_25c_FF.lib
synopsys_FF_3v_-40c_SS.lib
synopsys_FF_3v_-40c_TT.lib
synopsys_TT_4v_125c_TT.lib
synopsys_TT_10v_85c_TT.lib
synopsys_SS_1.2v_-40c_SS.lib
synopsys_SS_1.4v_-40c_SS.lib

Expecting:

synopsys_SS_1v_-40c_SS.lib
synopsys_TT_1v_85c_TT.lib
synopsys_SS_1.2v_-40c_SS.lib
synopsys_SS_1.4v_-40c_SS.lib
synopsys_SS_2v_-40c_SS.lib
synopsys_SS_2v_-40c_TT.lib
synopsys_FF_3v_25c_FF.lib
synopsys_FF_3v_-40c_SS.lib
synopsys_FF_3v_-40c_TT.lib
synopsys_TT_4v_125c_TT.lib
synopsys_TT_10v_85c_TT.lib

Any suggestions are greatly appreciated.

Edit: I ended up using the simpler method described by @StephenRauch:

import re
def sort_names(format_ids, selector, key=1):

    if isinstance(key, int):
        key = [key]

    SELECTOR_RE = re.compile(selector)

    def convert(x):
        try:
            return float(x[:-1])
        except ValueError:
            return x

    def sort_keys(key):
        def split_fid(x):
            x = SELECTOR_RE.split(x)
            return tuple([convert(x[i]) for i in key])
        return split_fid

    format_ids.sort(key=sort_keys(key))

format_ids = ["synopsys_SS_2v_-40c_SS.lib",
              "synopsys_SS_1v_-40c_SS.lib",
              "synopsys_SS_1.2v_-40c_SS.lib",
              "synopsys_SS_1.4v_-40c_SS.lib",
              "synopsys_SS_2v_-40c_TT.lib",
              "synopsys_FF_3v_25c_FF.lib",
              "synopsys_TT_4v_125c_TT.lib",
              "synopsys_TT_1v_85c_TT.lib",
              "synopsys_TT_10v_85c_TT.lib",
              "synopsys_FF_3v_-40c_SS.lib",
              "synopsys_FF_3v_-40c_TT.lib"]

selector = r'.*(FF|TT|SS)_([-\.\d]+v)_([-\.\d]+c)_(FF|TT|SS).*'
key = [2,1,3]

sort_names(format_ids,selector,key)

Stephen Rauch · Accepted Answer · 2017-07-03 18:34:15Z

1

Need to test for numbers a bit differently, and the re.split() is given a leading '' which was throwing off the convert routine.

Fixed Code:

key = [2,1,3]

def convert(x):
    try:
        return float(x)
    except ValueError:
        return x

alphanum_keys = lambda k: (convert(c) for c in re.split('([-.\d]+)', k))
alphanum_key = lambda k: [i for i in alphanum_keys(k) if i != ''][0]
split_list = lambda name: [
    alphanum_key(re.findall(selector, name)[0][i]) for i in key]
format_ids.sort(key=split_list)

Alternate (simpler) solution:

But... All of those lambdas and regexs, are way more complicated than you need for this problem. How about just:

def sort_key(keys):

    def convert(x):
        try:
            return float(x[:-1])
        except ValueError:
            return x

    def f(x):
        x = x.split('_')
        return tuple([convert(x[i]) for i in keys])
    return f

format_ids.sort(key=sort_key([3, 2, 4]))

How?

sort_keys() returns a function f(). This is a function of one parameter that is passed to sort() to evaluate sort order. The function f() will use the values of keys that are passed to sort_keys() because these are the values available at the time f() is defined. This is called a closure.

Results:

synopsys_SS_1v_-40c_SS.lib
synopsys_SS_1.2v_-40c_SS.lib
synopsys_SS_1.4v_-40c_SS.lib
synopsys_SS_2v_-40c_SS.lib
synopsys_SS_2v_-40c_TT.lib
synopsys_FF_3v_-40c_SS.lib
synopsys_FF_3v_-40c_TT.lib
synopsys_FF_3v_25c_FF.lib
synopsys_TT_1v_85c_TT.lib
synopsys_TT_10v_85c_TT.lib
synopsys_TT_4v_125c_TT.lib

edited Jul 3, 2017 at 18:34

answered Jun 30, 2017 at 3:00

Stephen Rauch♦

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8 Comments

Luca Over a year ago

@Steven\ Rauch, thanks for the alternate solution, I was trying to implement it but it's not working for me. In my case, I have to split by a user defined regex, so I replaced x.split('_') with x.split(selector). Given all this, where is f(x) called by?

Stephen Rauch Over a year ago

@Kidneys, I added an explanation of closures.. Let me know if that doesn't answer the where is it being called? Also be sure to pass selector to sort_keys if it will be used in f()

Luca Over a year ago

@Steven\ Rauch, I completely missed that one, thanks for clarifying. I just updated the code above and getting 'list index out of range error'. Where am I going wrong?

Stephen Rauch Over a year ago

@Kidneys, You are not doing a Regex Split, you are still doing a simple string split.

Luca Over a year ago

@StevenRauch, Just made a minor change to your edit and all is good now, Thanks!!

|

Tané Tachyon · Accepted Answer · 2017-06-30 02:36:11Z

1

A big part of your problem is that only actual digits are considered digits, not dashes and periods, so in your code things like "-40".isdigit() or "1.4".isdigit() would be False, and stay as text rather than being converted to floats.

answered Jun 30, 2017 at 2:36

Tané Tachyon

1,1108 silver badges11 bronze badges

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