import glob
from collections import Counter
from IPython.display import HTML
import pandas as pd

Another approach to question mark ratios: split each text into character counts (many additional rabbit holes open up here), in preparation for counting alternate ratios, like:

number of question marks / number of periods
number of question marks / number of commas
number of question marks / number of words

CORPUS_FOLDER = '/data/corpora/muncie_public_library_corpus/PG_no_backmatter_fiction/'

def charcount(filepath):
    text = open(filepath).read()
    filename = filepath.split("/")[-1]
    wordestimate = len(text.split())
    data = dict(Counter([t for t in text.strip()]))
    data['filename'] = filename
    data['wordcount'] = wordestimate
    return data

filepaths = glob.glob(CORPUS_FOLDER + "*.txt")

datalist = []
print("Checking texts and counting stuff …")
for (i, path) in enumerate(filepaths):
    if i % 100 == 0:
        print(i, path.split("/")[-1])
    datalist.append(charcount(path))
df = pd.DataFrame(datalist).fillna(0)

Checking texts and counting stuff …
0 Champney_Elizabeth_W_Elizabeth_Williams_Witch_Winnie_The_Story_of_a_King_s_Daughter_PG_34551_8.txt
100 MacDonald_George_Sir_Gibbie_PG_2370.txt
200 Black_William_In_Silk_Attire_A_Novel_PG_40111_0.txt
300 Abbott_Jacob_Rollo_in_Naples_PG_24488_8.txt
400 Ward_Humphry_Mrs_Helbeck_of_Bannisdale_Volume_II_PG_9442_8.txt
500 Caine_Hall_Sir_The_Scapegoat_PG_1303.txt
600 Hope_Anthony_The_Intrusions_of_Peggy_PG_47319_8.txt
700 Reid_Mayne_The_Young_Yagers_A_Narrative_of_Hunting_Adventures_in_Southern_Africa_PG_34668.txt
800 Ellis_Edward_Sylvester_The_Wilderness_Fugitives_PG_30335.txt

df.index = df['filename']
del(df['filename'])
df.columns = [c.replace("\t", "_t").replace("\n", "_n") for c in df.columns]

df['q_per_period'] = (df["?"]/df['.'])
df['q_per_comma'] = (df["?"]/df[','])
df['q_per_word'] = (df["?"]/df['wordcount'])

q = df.sort_values(by="q_per_period", ascending=False)[["?", ".",",", "q_per_period", "q_per_comma", "q_per_word", "wordcount"]]

display(HTML("<h1>Ranks</h1>"))
display(HTML("""<p><i>Jane Eyre</i> ranks 32nd among 883 novels in having a high ratio of question marks to periods. 
             It ranks 70th in ratio of question marks to total word count (estimated naively by splitting on space). 
             It ranks 24th in the absolute number of question marks.</p>"""))
q.rank(ascending=False).iloc[q.index.map(lambda x: x.startswith("Bront") or x.startswith("Marlitt"))]

display(HTML("<h1>Raw counts and ratios (Brontë and Marlitt)</h1>"))
q.iloc[q.index.map(lambda x: x.startswith("Bront") or x.startswith("Marlitt"))]

display(HTML("<h1>Raw counts and ratios for all the texts</h1>"))
with pd.option_context('display.max_rows', None, 'display.max_columns', None):
    display(q)

Our full dataframe includes columns for every single-character character in the corpus.

This is idle speculation, but when we take the ranks of all the columns and then look at just the row for Jane Eyre, is there anything to see by looking at the features where the novel ranks highly? These are raw counts, not ratios, and Jane Eyre is fairly lengthy (ranking 70th here in word count), so this is just to get an impression:

df.rank(ascending=False).loc["Bront_Charlotte_Jane_Eyre_An_Autobiography_PG_1260.txt"].sort_values().head(25)

:                1.0
{                5.0
}                7.0
I               10.0
&               11.0
;               13.0
?               24.0
q_per_period    32.0
q               43.0
x               51.0
J               51.0
-               53.0
"               54.0
d               58.0
m               59.0
y               63.0
                63.0
u               65.0
_n              66.0
(               66.5
)               67.0
Y               68.0
wordcount       70.0
s               72.0
c               75.0
Name: Bront_Charlotte_Jane_Eyre_An_Autobiography_PG_1260.txt, dtype: float64

Oddly, Jane Eyre ranks first in absolute number of colons.

Here's a sampling of fragments from the text where colons appear:

I was glad of it: I never liked long walks, especially on chilly
afternoons: dreadful to me was the coming home in the raw twilight, with
in the drawing-room: she lay reclined on a sofa by the fireside, and with
contained a bookcase: I soon possessed myself of a volume, taking care
seat: gathering up my feet, I sat cross-legged, like a Turk; and, having
I returned to my book   --   Bewick's History of British Birds: the letterpress
these death-white realms I formed an idea of my own: shadowy, like all
quickly: it was an object of terror.

The curly braces in this case are an artifact of how Project Gutenberg transcribed captions for illustrations.

{How dare I, Mrs. Reed?  How dare I?  Because it is the truth: p30.jpg}
{I was mortally afraid of its trampling forefeet: p107.jpg}
{"What is it and who did it?" he asked: p140.jpg}

I is interesting but not surprising evidence of our first-person narrator.

& in Jane Eyre, at least, is just a matter of about 20 instances of &c..

It does seem notable that Bronte uses lots of colons and semicolons, as well as lots of question marks.

	?	.	,	q_per_period	q_per_comma	q_per_word	wordcount
filename
Bront_Charlotte_Jane_Eyre_An_Autobiography_PG_1260.txt	24.0	95.0	119.0	32.0	105.0	97.0	70.0
Bront_Anne_The_Tenant_of_Wildfell_Hall_PG_969_0.txt	87.5	243.0	91.0	56.0	394.0	264.0	123.0
Bront_Charlotte_The_Professor_PG_1028.txt	436.0	665.0	398.0	90.0	459.0	382.0	457.0
Marlitt_Wister_Owls_Nest_corrected_4_21_2018.txt	202.0	391.0	374.0	107.0	174.0	152.0	390.0
Bront_Emily_Wuthering_Heights_PG_768.txt	175.0	352.0	264.0	111.0	239.0	196.0	300.0
Marlitt_Wister_Baliff.txt	517.0	724.0	719.0	127.0	142.0	241.0	652.0
Bront_Charlotte_Villette_PG_9182.txt	49.0	77.0	62.0	180.0	315.0	235.0	55.0
Marlitt_Wister_The_Second_Wife_corrected.txt	350.0	476.0	412.0	232.0	296.0	313.0	417.0
Marlitt_Wister_At_the_Councillor_s_or_A_Nameless_History_PG_43393_0.txt	318.5	417.0	342.0	252.0	340.0	390.0	316.0
Bront_Charlotte_Shirley_PG_30486.txt	20.0	19.0	58.0	277.0	138.0	130.0	32.0
Marlitt_Wister_Little_Moorland_Princess_cleaned_121817.txt	244.0	280.0	272.0	327.0	344.0	403.0	244.0
Marlitt_Wister_Lady_with_the_Rubies_corrected_3_13_208.txt	379.5	421.0	472.0	329.0	253.0	337.0	424.0
Marlitt_Wister_Gold_Elsie_PG_42426.txt	487.5	498.0	367.0	430.0	574.0	605.0	368.0
Marlitt_Wister_Countess_Gisela_corrected_4_10_2018.txt	434.0	419.0	277.0	453.0	607.0	638.0	274.5
Marlitt_Wister_OMS_translation_cleaned_110617.txt	524.5	554.0	481.0	477.0	538.0	613.0	447.0
Marlitt_Wister_Im Schillingshof_4_26_2018.txt	410.5	354.0	315.0	511.0	519.0	592.0	280.0

	?	.	,	q_per_period	q_per_comma	q_per_word	wordcount
filename
Bront_Charlotte_Jane_Eyre_An_Autobiography_PG_1260.txt	1497	8427	14535	0.177643	0.102993	0.007903	189418
Bront_Anne_The_Tenant_of_Wildfell_Hall_PG_969_0.txt	1013	6111	15674	0.165767	0.064629	0.006009	168589
Bront_Charlotte_The_Professor_PG_1028.txt	470	2996	7823	0.156876	0.060079	0.005235	89788
Marlitt_Wister_Owls_Nest_corrected_4_21_2018.txt	728	4785	8185	0.152142	0.088943	0.007121	102232
Bront_Emily_Wuthering_Heights_PG_768.txt	779	5142	9892	0.151497	0.078751	0.006639	117334
Marlitt_Wister_Baliff.txt	380	2561	4073	0.148380	0.093297	0.006174	61549
Bront_Charlotte_Villette_PG_9182.txt	1233	8910	17352	0.138384	0.071058	0.006250	197282
Marlitt_Wister_The_Second_Wife_corrected.txt	552	4184	7614	0.131931	0.072498	0.005667	97410
Marlitt_Wister_At_the_Councillor_s_or_A_Nameless_History_PG_43393_0.txt	593	4597	8597	0.128997	0.068978	0.005183	114412
Bront_Charlotte_Shirley_PG_30486.txt	1637	13092	17477	0.125038	0.093666	0.007481	218827
Marlitt_Wister_Little_Moorland_Princess_cleaned_121817.txt	664	5648	9688	0.117564	0.068538	0.005114	129848
Marlitt_Wister_Lady_with_the_Rubies_corrected_3_13_208.txt	530	4527	6880	0.117075	0.077035	0.005492	96496
Marlitt_Wister_Gold_Elsie_PG_42426.txt	421	4001	8238	0.105224	0.051105	0.004035	104336
Marlitt_Wister_Countess_Gisela_corrected_4_10_2018.txt	471	4555	9651	0.103403	0.048803	0.003834	122852
Marlitt_Wister_OMS_translation_cleaned_110617.txt	367	3640	6761	0.100824	0.054282	0.003994	91878
Marlitt_Wister_Im Schillingshof_4_26_2018.txt	499	5123	8906	0.097404	0.056030	0.004096	121835

	?	.	,	q_per_period	q_per_comma	q_per_word	wordcount
filename
Warner_Susan_Melbourne_House_PG_18686_8.txt	2693	12332	12882	0.218375	0.209051	0.015145	177813
Wiggin_Kate_Douglas_Smith_The_Story_of_Patsy_PG_13506.txt	113	520	986	0.217308	0.114604	0.009365	12066
Kingsley_Charles_Westward_Ho_Or_The_Voyages_and_Adventures_of_Sir_Amya_PG_1860.txt	1845	8568	26005	0.215336	0.070948	0.007260	254125
Auerbach_Berthold_Christian_Gellert_s_Last_Christmas_From_German_Tales_PG_22665_8.txt	69	329	892	0.209726	0.077354	0.006660	10361
Carroll_Lewis_Alice_s_Adventures_in_Wonderland_PG_11.txt	202	990	2418	0.204040	0.083540	0.007494	26954
Lincoln_Jeanie_Gould_An_Unwilling_Maid_Being_the_History_of_Certain_Ep_PG_10958_8.txt	352	1738	4501	0.202532	0.078205	0.006969	50511
Mathews_Frances_Aymar_My_Lady_Peggy_Goes_to_Town_PG_50388_8.txt	379	1886	6590	0.200954	0.057511	0.006043	62720
Warner_Susan_The_Wide_Wide_World_PG_18689_8.txt	2655	13279	21020	0.199940	0.126308	0.010381	255750
Morris_Clara_A_Pasteboard_Crown_A_Story_of_the_New_York_Stage_PG_35055.txt	596	2998	8766	0.198799	0.067990	0.006108	97580
Weyman_Stanley_John_Count_Hannibal_A_Romance_of_the_Court_of_France_PG_15763.txt	1157	5926	9615	0.195241	0.120333	0.010338	111915
Otis_James_Corporal_Lige_s_Recruit_A_Story_of_Crown_Point_and_Ticonderoga_PG_33110.txt	206	1068	2149	0.192884	0.095859	0.005950	34623
Aguilar_Grace_The_Days_of_Bruce_Vol_1_A_Story_from_Scottish_History_PG_18387_8.txt	735	3850	15106	0.190909	0.048656	0.005076	144790
Dumas_Alexandre_Twenty_Years_After_PG_1259_8.txt	2445	13026	21923	0.187702	0.111527	0.010026	243861
Alger_Horatio_Sam_s_Chance_and_How_He_Improved_It_PG_26043.txt	679	3638	3133	0.186641	0.216725	0.016985	39976
Austin_Jane_G_Jane_Goodwin_Outpost_PG_4676.txt	619	3337	8674	0.185496	0.071363	0.007643	80990
Weyman_Stanley_John_Sophia_A_Romance_PG_39168.txt	1197	6460	10115	0.185294	0.118339	0.010861	110213
Voynich_E_L_Ethel_Lillian_The_Gadfly_PG_3431.txt	975	5262	6200	0.185291	0.157258	0.009540	102204
Duchess_Airy_Fairy_Lilian_PG_35228.txt	1291	6978	12677	0.185010	0.101838	0.009702	133070
Pansy_Three_People_PG_20808.txt	833	4506	6866	0.184865	0.121322	0.009689	85976
Dickinson_Anna_E_Anna_Elizabeth_What_Answer_PG_15402.txt	487	2645	7327	0.184121	0.066466	0.007159	68025
Harland_Henry_The_Cardinal_s_Snuff_Box_PG_5610.txt	680	3727	5131	0.182452	0.132528	0.012849	52922
Lytton_Edward_Bulwer_Lytton_Baron_The_Last_Days_of_Pompeii_PG_1565.txt	951	5229	12846	0.181870	0.074031	0.006162	154324
Warner_Susan_Queechy_PG_8874_8.txt	2807	15436	17312	0.181848	0.162142	0.009843	285180
Hope_Anthony_A_Change_of_Air_PG_45749.txt	695	3829	4947	0.181510	0.140489	0.012165	57130
Kingsley_Charles_Alton_Locke_Tailor_and_Poet_An_Autobiography_PG_8374.txt	1212	6703	18052	0.180815	0.067139	0.006290	192694
Spielhagen_Friedrich_What_the_Swallow_Sang_A_Novel_PG_34599.txt	618	3423	8532	0.180543	0.072433	0.005968	103549
Evans_Augusta_J_Augusta_Jane_Infelice_PG_17718_8.txt	1399	7757	15234	0.180353	0.091834	0.007315	191247
Von_Arnim_Elizabeth_The_Benefactress_PG_30302_8.txt	1013	5637	8971	0.179706	0.112919	0.008721	116159
Weyman_Stanley_John_Shrewsbury_A_Romance_PG_39137_8.txt	929	5171	11489	0.179656	0.080860	0.007255	128054
Dickens_Charles_Our_Mutual_Friend_PG_883.txt	2778	15580	31480	0.178306	0.088247	0.008454	328584
May_Sophie_Dotty_Dimple_at_Her_Grandmother_s_PG_20699.txt	258	1451	2248	0.177808	0.114769	0.010518	24529
Bront_Charlotte_Jane_Eyre_An_Autobiography_PG_1260.txt	1497	8427	14535	0.177643	0.102993	0.007903	189418
Finley_Martha_Elsie_s_Kith_and_Kin_PG_14488.txt	572	3230	7383	0.177090	0.077475	0.007696	74323
Evans_Augusta_J_Augusta_Jane_At_the_Mercy_of_Tiberius_PG_4209.txt	1160	6595	14967	0.175891	0.077504	0.006376	181941
Richards_Laura_Elizabeth_Howe_Geoffrey_Strong_PG_8877.txt	338	1941	2581	0.174137	0.130957	0.010825	31224
Carlyle_Thomas_Sartor_Resartus_and_On_Heroes_Hero_Worship_and_the_Heroic_in_History_PG_20585_8.txt	914	5250	18560	0.174095	0.049246	0.005142	177745
Isham_Frederic_Stewart_The_Strollers_PG_29726.txt	876	5033	9084	0.174051	0.096433	0.007955	110125
Weyman_Stanley_John_The_Castle_Inn_PG_11918_8.txt	1146	6589	9683	0.173926	0.118352	0.010253	111773
Finley_Martha_The_Two_Elsies_A_Sequel_to_Elsie_at_Nantucket_PG_13379.txt	472	2714	5432	0.173913	0.086892	0.007344	64270