python如何将数据框中的一列转换为日期和绘制

Question

我有一个数据帧df，如下所示：

df = pd.DataFrame({'date': [20121231,20130102, 20130105, 20130106, 20130107, 20130108],'price': [25, 163, 235, 36, 40, 82]})

如何将df['date']设为date type并将'price'设为y-label和'date'设为x-label？

非常感谢。

Answer 1

将to_datetime与参数format一起使用，选中http://strftime.org/：

df['date'] = pd.to_datetime(df['date'], format='%Y%m%d')
print (df)
        date  price
0 2012-12-31     25
1 2013-01-02    163
2 2013-01-05    235
3 2013-01-06     36
4 2013-01-07     40
5 2013-01-08     82

然后是plot：

df.plot(x='date', y='price')

Answer 2

import pandas as pd
%matplotlib inline
df = pd.DataFrame({'date': [20121231,20130102, 20130105, 20130106, 20130107, 
                            20130108],'price': [25, 163, 235, 36, 40, 82]})
df['date'] = pd.to_datetime(df['date'], format='%Y%m%d')

df.plot(x='date', y='price')

Answer 3

使用import json import subprocess filename = "/home/umesh/Downloads/scripts/cloud-init.log" def convert_to_json_log(line): """ convert each line to json format """ log = {} log['msg'] = line log['logger-name'] = 'cloud-init' log['ServiceName'] = 'Contentprocessing' return json.dumps(log) def log_as_json(filename): f = subprocess.Popen(['cat','-F',filename], stdout=subprocess.PIPE,stderr=subprocess.PIPE) while True: line = f.stdout.readline() log = convert_to_json_log(line) print log with open("/home/umesh/Downloads/outputs/cloud-init-json.log", 'a') as new: new.write(log + '\n') log_as_json(filename) ，您可以将 date 列直接转换为pandas类型。然后，您可以使用datetime进行绘制。看看this answer以及this one。

matplotlib

结果：