量化2015-2017年间911呼叫数与年份的关系

import pandas as pd
import numpy as np
from matplotlib import pyplot as plt

一、加载数据

df = pd.read_csv("./911.csv")
df["timeStamp"] = pd.to_datetime(df["timeStamp"])
print(type(df["timeStamp"]))
df.set_index("timeStamp", inplace=True)
df.head(3)

<class 'pandas.core.series.Series'>

二、利用df.resample()统计

count_by_month = df.resample("M").count()["title"]
count_by_month.head(3)

timeStamp
2015-12-31     7916
2016-01-31    13096
2016-02-29    11396
Freq: M, Name: title, dtype: int64

三、绘图

_x = count_by_month.index
_y = count_by_month.values

print(type(_x[0]))
_x = [i.strftime("%Y%m%d") for i in _x]
print(_x[0])


plt.figure(figsize=(20,8),dpi=80)

plt.plot(range(len(_x)),_y)

plt.xticks(range(len(_x)),_x, rotation=45)

plt.show()

<class 'pandas._libs.tslibs.timestamps.Timestamp'>
20151231