How to check if a ticker is yfinance library

Question

I'm trying to find some information on some tickers through yfinance. However, I run into an error whenever I try to search up information on a ticker that doesn't exist. For example, this is the code I had.

import yfinance as yf

with open("/2019.txt") as f:
    content = f.readlines()
# content is a list with all tickers in "/2019.txt"
content = [x.strip() for x in content] 

print(content)

for x in content:
    y = yf.Ticker(x)
    z = y.info['volume']
    print(x)
    print(z)

This is the error I received:

/usr/local/lib/python3.6/dist-packages/yfinance/base.py in _get_fundamentals(self, kind, proxy)
        338                 self._info.update(data[item])
        339 
    --> 340         self._info['regularMarketPrice'] = self._info['regularMarketOpen']
        341         self._info['logo_url'] = ""
        342         try:
    
    KeyError: 'regularMarketOpen'

To fix this I tried:

import yfinance as yf

with open("/2019.txt") as f:
    content = f.readlines()
# content is a list with all tickers in "/2019.txt"
content = [x.strip() for x in content] 

print(content)

for x in content:
    y = yf.Ticker(x)
    if(y==1):
      z = y.info['volume']
      print(x)
      print(z)
    elif(y==0):
      print(y)
      print( "does not exist")

But now it doesn't print anything except the tickers in the list.

Does anyone know how to approach this? Thanks!

Answer 1

2/22/23 Update

There are increasing issues using the info method in the yfinance library. Most recent issues are discussed here: https://github.com/ranaroussi/yfinance/issues/1407. For those looking to get a check, an alternative approach is to simply use the history method and check if there is recently-available data. For example, the following is output from yf.Ticker('SPY').history(period='7d', interval='1d'):

                                Open        High  ...  Stock Splits  Capital Gains
Date                                               ...                             
2023-02-10 00:00:00-05:00  405.859985  408.440002  ...           0.0            0.0
2023-02-13 00:00:00-05:00  408.720001  412.970001  ...           0.0            0.0
2023-02-14 00:00:00-05:00  411.239990  415.049988  ...           0.0            0.0
2023-02-15 00:00:00-05:00  410.350006  414.059998  ...           0.0            0.0
2023-02-16 00:00:00-05:00  408.790009  412.910004  ...           0.0            0.0
2023-02-17 00:00:00-05:00  406.059998  407.510010  ...           0.0            0.0
2023-02-21 00:00:00-05:00  403.059998  404.160004  ...           0.0            0.0

For a non-trading asset (FAKENAME in this case) the following output is seen:

FAKENAME: No data found, symbol may be delisted

An approach for wrapping that into a concise function that gives a True/False output would be as follows:

def check_available(asset: str) -> bool:
    """
    Checks if an asset is available via the Yahoo Finance API.
    """
    info = yf.Ticker(asset).history(
        period='7d',
        interval='1d')
    # return == period value for more precise check but may
    # need more complex handling to take into account non-
    # trading days, holidays, etc.
    return len(info) > 0

Essentially, this says "an asset is available if there is recently data" which may not be true in all cases so keep that in mind.

Answer 2

Try to get the info of the ticker and if you get an exception you probably cannot do much more with it:

import yfinance as yf

for t in ["MSFT", "FAKE"]:
  ticker = yf.Ticker(t)
  info = None

  try:
    info = ticker.info
  except:
    print(f"Cannot get info of {t}, it probably does not exist")
    continue
  
  # Got the info of the ticker, do more stuff with it
  print(f"Info of {t}: {info}")

See a demo on this colab.