python - 字符串没有属性 .loc

Question

我有不同的数据框遵循这个例子：'AAPLdf，AMZNdf，GOOGLdf，......'等等

import matplotlib.pyplot as plt
from mpl_finance import candlestick_ohlc
import pandas as pd
import matplotlib.dates as mpl_dates

ticker = input("ticker:") + "df"

data = ticker
ohlc = data.loc[:, ['t', 'o', 'h', 'l', 'c']]

AttributeError：“str”对象没有属性“loc”

Answer 1

• eval()是一个内置的python函数
• f'{variable}'是一个 f 字符串
  • f-Strings：一种在 Python 中格式化字符串的新方法和改进方法
  • PEP 498 - 文字字符串插值

ticker = input('ticker: ')

# this will return data as the dataframe from ticker, but it must be an exact match
data = eval(f'{ticker}df')  # -> equivalent to eval('GOOGLdf`), for example

# now you can use .loc 
data.loc[:, :]