无法绘制蜡烛图

Question

我正在尝试打开一个 csv 文件，并绘制一个蜡烛图，但出现了一个错误：

Traceback (most recent call last):
  File "/media/shutruk/Data/projects/money/qwerty.py", line 28, in <module>
    plot_candlestick(data_json)
  File "/media/shutruk/Data/projects/money/qwerty.py", line 14, in plot_candlestick
    ohlc = [(mdates.datestr2num(d[0]), d[2], d[3], d[4], d[1]) for d in data]
  File "/media/shutruk/Data/projects/money/qwerty.py", line 14, in <listcomp>
    ohlc = [(mdates.datestr2num(d[0]), d[2], d[3], d[4], d[1]) for d in data]
KeyError: 0

下面是整个代码：

import matplotlib.pyplot as plt
from mplfinance.original_flavor import candlestick_ohlc
import matplotlib.dates as mdates
import csv

file_path = 'data.csv'

def plot_candlestick(data):
  if len(data) > 100:
    data = data[-100:]

  fig, ax = plt.subplots()
  
  ohlc = [(mdates.datestr2num(d[0]), d[2], d[3], d[4], d[1]) for d in data]
  candlestick_ohlc(ax, ohlc, width=0.6, colorup='red', colordown='green')

  ax.xaxis_date()
  ax.xaxis.set_major_formatter(mdates.DateFormatter('%Y-%m-%d'))
  plt.gcf().autofmt_xdate()
  plt.subplots_adjust(left=0.05, right=0.85, top=0.90, bottom=0.10)
  
  plt.show()

with open(file_path, 'r') as file:
  reader = csv.DictReader(file)    
  data_json = [row for row in reader]

plot_candlestick(data_json)

这个 csv 文件的内容看起来是这样的：

"Date","Price","Open","High","Low","Vol.","Change %"
"03/27/2024","70,285.4","69,999.2","70,714.1","69,459.5","82.93K","0.41%"
"03/26/2024","69,999.3","69,896.3","71,490.7","69,366.4","90.98K","0.15%"
"03/25/2024","69,892.0","67,216.4","71,118.8","66,395.0","124.72K","3.99%"
"03/24/2024","67,211.9","64,036.5","67,587.8","63,812.9","65.59K","4.96%"
"03/23/2024","64,037.8","63,785.6","65,972.4","63,074.9","35.11K","0.40%"
"03/22/2024","63,785.5","65,501.5","66,633.3","62,328.3","72.43K","-2.62%"
"03/21/2024","65,503.8","67,860.0","68,161.7","64,616.1","75.26K","-3.46%"
"03/20/2024","67,854.0","62,046.8","68,029.5","60,850.9","133.53K","9.35%"

请告诉我怎么解决这个问题。

Answer 1

这里的d是一个字典，而data是一个列表。我已经调试了你的代码，结果显示如下：

错误发生的原因是，CSV读取器返回的是一个字典，其中键是列名，值是每一行对应的值。

要解决这个问题，你可以修改你的代码，通过列名来访问值，而不是通过索引。以下是修正后的代码：

import matplotlib.pyplot as plt
from mplfinance.original_flavor import candlestick_ohlc
import matplotlib.dates as mdates
import csv

file_path = 'data.csv'

def plot_candlestick(data):
    if len(data) > 100:
        data = data[-100:]

    fig, ax = plt.subplots()

    ohlc = [(mdates.datestr2num(d["Date"]), float(d["Open"].replace(",", "")), float(d["High"].replace(",", "")), float(d["Low"].replace(",", "")), float(d["Price"].replace(",", ""))) for d in data]
    candlestick_ohlc(ax, ohlc, width=0.6, colorup='red', colordown='green')

    ax.xaxis_date()
    ax.xaxis.set_major_formatter(mdates.DateFormatter('%Y-%m-%d'))
    plt.gcf().autofmt_xdate()
    plt.subplots_adjust(left=0.05, right=0.85, top=0.90, bottom=0.10)

    plt.show()

with open(file_path, 'r') as file:
    reader = csv.DictReader(file)
    data_json = [row for row in reader]

plot_candlestick(data_json)

Answer 2

d代表的是数据列表中的一个字典，它和用键来访问值（比如 d['Date']、d['Open'] 等）是不一样的。我已经修改了那部分内容。

需要把数字列中的逗号去掉（比如 Open、High、Low、Price），然后把它们转换成浮点数。所以，我把你的代码 ohlc = [(mdates.datestr2num(d[0]), d[2], d[3], d[4], d[1]) for d in data] 改成了这样。

我用你的 CSV 示例测试过，这样是可以工作的。

def plot_candlestick(data):
    if len(data) > 100:
        data = data[-100:]

    fig, ax = plt.subplots()
    
    ohlc = [(mdates.datestr2num(d['Date']), float(d['Open'].replace(',', '')), float(d['High'].replace(',', '')), float(d['Low'].replace(',', '')), float(d['Price'].replace(',', ''))) for d in data]
    candlestick_ohlc(ax, ohlc, width=0.6, colorup='red', colordown='green')

    ax.xaxis_date()
    ax.xaxis.set_major_formatter(mdates.DateFormatter('%Y-%m-%d'))
    plt.gcf().autofmt_xdate()
    plt.subplots_adjust(left=0.05, right=0.85, top=0.90, bottom=0.10)
    
    plt.show()


plot_candlestick(data)