PandasDataSource.update creates datasource with nan

since v 1.5.1

Code that creates nans after ds merge

PandasDataSource.update()

input_df = pd.merge(input_df, df[[]], how='outer', left_index=True, right_index=True)

input_df = input_df.dropna() seems solves the issue

Steps to reproduce the issue:

1. Set a breakpoint to the line described above
2. Run example code and press u keypress to update ds

#!/usr/bin/env python3
from datetime import datetime, timedelta

import finplot as fplt
import yfinance as yf
from PyQt5.QtGui import QApplication, QGridLayout
from PyQt5.QtWidgets import QGraphicsView, QLabel

app = QApplication([])
win = QGraphicsView()
win.setWindowTitle('TradingView wannabe')
layout = QGridLayout()
win.setLayout(layout)
win.resize(600, 500)

info = QLabel()
layout.addWidget(info, 0, 1, 1, 1)

ax = fplt.create_plot()
win.axs = [ax] # finplot requres this property
layout.addWidget(ax.vb.win, 1, 0, 1, 2)

barsDate = datetime.fromisoformat("2021-03-12T21:15:55")
offset = timedelta(days=1)

def download(symbol):
    global barsDate
    items = yf.download(symbol, start=(barsDate).strftime("%Y-%m-%d"), end=(barsDate + offset).strftime("%Y-%m-%d"), interval='15m')
    print((barsDate + offset).strftime("%Y-%m-%d") + " - " + barsDate.strftime("%Y-%m-%d"))
    barsDate -= offset
    return items

plots = []
def update():
    df = download("AMD")
    if len(df) < 20: # symbol does not exist
        return
    price = df['Open Close High Low'.split()]
    if not plots:
        plots.append(fplt.candlestick_ochl(price))
    else:
        plots[0].update_data(price)

def _key_pressed(vb, ev):
    if ev.text() == 'u':
        update()

fplt._key_pressed = _key_pressed

update()
fplt.show(qt_exec=False) # prepares plots when they're all setup
win.show()
app.exec_()

[highfestiva]

Many people ask for similar stuff, so added a reset functionality in 4a30ba28abd37a22155fef646f9003979ef61129. Use like so:

    price = df['Open Close High Low'.split()]
    ax.reset()
    fplt.candlestick_ochl(price)
    fplt.refresh()

No need to store plots for later, just reset and plot again. GL!

[highfestiva]

I’ve included this functionality in an example.