import pandas as pd
import pymysql
import numpy as np


db = pymysql.connect(host='localhost', user='root', passwd='',
                  database='mom_db', charset='utf8')
df = pd.read_sql("SELECT * FROM comments ", db)
cursor = db.cursor()

name = df['nickname']

count = pd.value_counts(name)

a = {count.index[i]:count[i] for i in range(len(count))}
print(a)
#print(count[count>1])-вывод Series

{'repeinik': 26, 'podberezowik': 24, 'Павел_Шуков_talks48': 20, 'stupich':
14, 'kipovets': 14, 'Лайош_Портиш': 13, 'vijigau_mraz': 13, 'наивная баба':
12, 'genek77': 12, 'Sergey_Petrov': 12, 'Андрей_Иванов_talks19': 11,
'Пачотны тунеядзец': 10, 'eugenenus_': 10, 'Настя_Романова': 9, 'Kac_Lol':
9, 'Ириша_Лалапусечка': 9, 'valstar78': 8, 'Сергей Александрович': 8,
'Tadeush_Тадеуш': 8, 'freedom for us': 7, 'Светлана_Малышкина': 7,
'Костя_Миронов': 7, 'SIgarA': 6, 'Жанна_Д-урк': 6, 'Fair play': 6,
'Лукашенко_Федор': 6, 'Lisa_Grodno': 5, 'id350886439': 5,......

repeinik                  26
podberezowik              24
Павел_Шуков_talks48       20
stupich                   14
kipovets                  14
Лайош_Портиш              13
.......

d = {'repeinik': 26, 'podberezowik': 24, 'Павел_Шуков_talks48': 20, 'stupich': 14, 'kipovets': 14, 'Лайош_Портиш': 13, 'vijigau_mraz': 13, 'наивная баба': 12, 'genek77': 12}

print("{:<20} {:<15}".format('Name','Value'))
for v in d.items():
    name, val = v
    print("{:<20} {:<15}".format(name, val))

Name                    Value
repeinik                26
podberezowik            24
Павел_Шуков_talks48     20
...                     ...

# pip install tabulate
from tabulate import tabulate

d = {'repeinik': 26, 'podberezowik': 24, 'Павел_Шуков_talks48': 20,
     'stupich': 14, 'kipovets': 14, 'Лайош_Портиш': 13,
     'vijigau_mraz': 13, 'наивная баба': 12, 'genek77': 12}
print(tabulate(d.items(), headers=['NAME', 'VALUE'], tablefmt="grid"))

+---------------------+---------+
| NAME                |   VALUE |
+=====================+=========+
| repeinik            |      26 |
+---------------------+---------+
| podberezowik        |      24 |
+---------------------+---------+
| Павел_Шуков_talks48 |      20 |
+---------------------+---------+
| stupich             |      14 |
+---------------------+---------+
| kipovets            |      14 |
+---------------------+---------+
| Лайош_Портиш        |      13 |
+---------------------+---------+
| vijigau_mraz        |      13 |
+---------------------+---------+
| наивная баба        |      12 |
+---------------------+---------+
| genek77             |      12 |
+---------------------+---------+

print('{:<20} {:<15}'.format('NickName', 'Numb_comm'))
for name, n_comm in a.items():
   print('{:<20} {:<15}'.format(name, n_comm))

NickName             Numb_comm
repeinik             26
podberezowik         24
Павел_Шуков_talks48  20
stupich              14
kipovets             14
Лайош_Портиш         13
vijigau_mraz         13
наивная баба         12
genek77              12

In [41]: df = pd.DataFrame({
                 'name':np.random.choice(['aaa','bbb','ccc'], 500, p=[0.55, .3, .15])
              })

In [42]: df
Out[42]:
    name
0    ccc
1    aaa
2    ccc
3    aaa
4    aaa
5    bbb
6    bbb
..   ...
493  aaa
494  bbb
495  aaa
496  aaa
497  aaa
498  bbb
499  aaa

[500 rows x 1 columns]

In [43]: df.groupby('name').size()
Out[43]:
name
aaa    269
bbb    153
ccc     78
dtype: int64

In [44]: df.groupby('name').size().reset_index(name='count')
Out[44]:
  name  count
0  aaa    269
1  bbb    153
2  ccc     78