Making Charts with Pandas

Line chart

import pandas as pd
user_df = pd.read_csv("https://raw.githubusercontent.com/p4css/py4css/main/data/twitter_user1_hashed.csv")
user_df['account_creation_date'] = pd.to_datetime(user_df['account_creation_date'], format="%Y-%m-%d")
user_df['account_creation_ym'] = user_df['account_creation_date'].dt.to_period("M")

sum_df = user_df.groupby('account_creation_ym')['userid'].count().reset_index(name='n')
print(type(sum_df))
sum_df

<class 'pandas.core.frame.DataFrame'>

	account_creation_ym	n
0	2008-05	1
1	2008-07	1
2	2008-11	1
3	2009-01	1
4	2009-02	1
...	...	...
98	2019-01	8
99	2019-02	12
100	2019-03	4
101	2019-04	4
102	2019-05	12

103 rows × 2 columns

month_count = user_df['account_creation_ym'].value_counts().reset_index(name='n')
month_count = month_count.sort_values('index', ascending=True)

---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
Cell In[3], line 2
      1 month_count = user_df['account_creation_ym'].value_counts().reset_index(name='n')
----> 2 month_count = month_count.sort_values('index', ascending=True)

File ~/anaconda3/lib/python3.10/site-packages/pandas/core/frame.py:7176, in DataFrame.sort_values(self, by, axis, ascending, inplace, kind, na_position, ignore_index, key)
   7170     indexer = lexsort_indexer(
   7171         keys, orders=ascending, na_position=na_position, key=key
   7172     )
   7173 elif len(by):
   7174     # len(by) == 1
-> 7176     k = self._get_label_or_level_values(by[0], axis=axis)
   7178     # need to rewrap column in Series to apply key function
   7179     if key is not None:
   7180         # error: Incompatible types in assignment (expression has type
   7181         # "Series", variable has type "ndarray")

File ~/anaconda3/lib/python3.10/site-packages/pandas/core/generic.py:1910, in NDFrame._get_label_or_level_values(self, key, axis)
   1908     values = self.axes[axis].get_level_values(key)._values
   1909 else:
-> 1910     raise KeyError(key)
   1912 # Check for duplicates
   1913 if values.ndim > 1:

KeyError: 'index'

import pandas as pd
import matplotlib.pyplot as plt
month_count.plot(x = 'index', y = 'n')

<AxesSubplot:xlabel='index'>

plt.rcParams['figure.dpi'] = 100
month_count.plot(x = 'index', y = 'n', figsize=(10, 5))

<AxesSubplot:xlabel='index'>

Plot resolution

• https://stackoverflow.com/questions/39870642/matplotlib-how-to-plot-a-high-resolution-graph

• Best result: plt.savefig('filename.pdf')

• To png: plt.savefig('filename.png', dpi=300)

Adjust resolution

• For saving the graph: matplotlib.rcParams['savefig.dpi'] = 300

• For displaying the graph when you use plt.show(): matplotlib.rcParams["figure.dpi"] = 100

import matplotlib.pyplot as plt
plt.rcParams['figure.dpi'] = 150
month_count.plot(x = 'index', y = 'n')
# plt.savefig("fig.pdf")

<AxesSubplot:xlabel='index'>

Bar chart

lang_count = user_df['account_language'].value_counts().reset_index(name="n").sort_values('n', ascending=False).rename(columns={"index":"account_language"})
lang_count

	account_language	n
0	zh-cn	569
1	en	104
2	ru	36
3	zh-CN	13
4	zh-tw	10
5	es	8
6	en-gb	3
7	ja	1

lang_count.plot(kind="bar", x="account_language")

<AxesSubplot:xlabel='account_language'>

Coordinate-flip

lang_count.plot(kind="barh", x="account_language")
lang_count.plot.barh(x="account_language").invert_yaxis()

plt.show()

Plot with Chinese font

import pandas as pd
drug_df = pd.read_csv('https://raw.githubusercontent.com/p4css/py4css/main/data/drug_156_2.csv')
pat1 = '代購|帶回'
pat2 = '蝦皮|露天|拍賣|YAHOO|商店街'
filtered_drug_df = drug_df.loc[drug_df['違規產品名稱'].str.contains(pat=pat1, na=False) & 
                               drug_df['刊播媒體'].str.contains(pat=pat2, na=False)]
filtered_drug_df

	違規產品名稱	違規廠商名稱或負責人	處分機關	處分日期	處分法條	違規情節	刊播日期	刊播媒體類別	刊播媒體	查處情形
2	✈日本 代購 參天製藥 處方簽點眼液	蘇O涵/蘇O涵	NaN	01 25 2022 12:00AM	NaN	無照藥商	08 27 2021 12:00AM	網路	蝦皮購物	NaN
3	✈日本 代購 TSUMURA 中將湯 24天包裝	蘇O涵/蘇O涵	NaN	01 25 2022 12:00AM	NaN	無照藥商	08 27 2021 12:00AM	網路	蝦皮購物	輔導結案
4	_Salty.shop 日本代購 樂敦小花	曾O嫺/曾O嫺	NaN	02 17 2022 12:00AM	藥事法第27條	無照藥商	12 6 2021 12:00AM	網路	蝦皮購物	處分結案
9	現貨正品 Eve 快速出貨 日本代購 白兔60 藍兔 40 eve 金兔 EVE 兔子 娃娃...	張O恩/張O恩	NaN	03 4 2022 12:00AM	NaN	無照藥商	12 21 2021 12:00AM	網路	蝦皮拍賣網站	輔導結案
18	[海外代購]纈草根膠囊-120毫克-240粒-睡眠	江O君/江O君	NaN	03 15 2022 12:00AM	NaN	無照藥商	08 2 2021 12:00AM	網路	蝦皮購物	NaN
...	...	...	...	...	...	...	...	...	...	...
2947	「泰國代購🇹🇭」泰國🇹🇭Hirudoid強效去疤膏（預購）	魏O芝/魏O芝	NaN	06 5 2020 12:00AM	藥事法第27條	無照藥商	12 17 2019 12:00AM	網路	蝦皮購物	處分結案
2948	eBuy美國代購美国正品GNC银杏叶精华提高增强记忆力预防老年痴呆补脑健脑	蕭O雄/蕭O雄	NaN	NaN	NaN	無照藥商	03 9 2020 12:00AM	網路	蝦皮購物	NaN
2957	【現貨】H&H 久光 Hisamitsu酸痛舒緩貼布 120枚 140枚 痠痛 舒緩 貼布 ...	胡OO/胡OO	NaN	07 16 2020 12:00AM	藥事法第27條	無照藥商	02 27 2020 12:00AM	網路	蝦皮購物	處分結案
2965	美國代購 ，9:5%折扣落建髮洗，兩款都有	陳O鵬/陳O鵬	NaN	07 16 2020 12:00AM	NaN	藥品未申請查驗登記	04 16 2020 12:00AM	網路	樂購蝦皮股份有限公司	輔導結案
2969	日本帶回樂敦小花新鮮貨	張O萍/張O萍	NaN	06 23 2020 12:00AM	NaN	難以判定產品屬性	03 10 2020 12:00AM	網路	蝦皮購物	輔導結案

420 rows × 10 columns

media_count = filtered_drug_df['刊播媒體'].value_counts().reset_index(name = "n").rename(columns={"index": "media"})

plt.rcParams['figure.dpi'] = 150
plt.rcParams['font.family'] = ['Heiti TC']

media_count.plot.barh(x="media").invert_yaxis()

# plt.show()