Progress Bars in Python(samwilkinson.io)

17 pointsby sammycdubs8 jaar geleden8 comments

https://samwilkinson.io/article/2018/12/17/progress-bars-python/

9 comments

I've always just used `sys.stdout.write("\r%i/%i" %(c, n)); sys.stdout.flush()`

That is exactly what this library does: "tqdm does not require any dependencies (not even curses!), just Python and an environment supporting carriage return \r and line feed \n control characters." -- https://github.com/tqdm/tqdm

Seems unnecessary imo to depend on an external library just to wrap and auto-prettify those 2 stdout commands.

cirgue8 jaar geleden

Can you provide an example snippet?

user24266798 jaar geleden

edit: how the hell does markdown/code-snippet work on hackernews?! Nicely formatted pic of the below text soup:

https://i.imgur.com/fvEeaJA.png

My library function is:

import sys def writeToTerminal(txt, line_len=79): # line_len is the max num of characters that can fit onto a terminal line without overflowing to a newline

		# overwrite the line with blank spaces
		# this takes care of the case where len(txt) is fewer than the [ len(txt) when this function was last called ]
		sys.stdout.write( "\r" + " "*line_len )
		sys.stdout.flush()
        
		# write the txt, trimming to line_len
		sys.stdout.write( "\r" + txt.replace("\t", "    ")[:line_len] )
		sys.stdout.flush()

Example usage:

from time import sleep L = list(range(10)) for c, i in enumerate(L, start=1): writeToTerminal("%i / %i" %(c, len(L))) sleep(1)

dragonwriter8 jaar geleden

> how the hell does markdown/code-snippet work on hackernews?!

It doesn't.

You can indent two spaces to get monospaced, unwrapped text, and that’s all the code formatting you get.

detaro8 jaar geleden

So it doesn't autodetect the terminal width, and thus doesn't do the same as the library?

cat1998 jaar geleden

it shows a progress indicator, which is functionally the same from a user perspective.

the visual display of this progress indicator is different yes -

This method doesn't need any notion of terminal width because it just prints 'N / N' at the beginning of the current line where the cursor is when called.

user24266798 jaar geleden

I tend to side with your opinion (obviously, based on the above code), but detaro does have a point, which is that the progress message will "overflow" onto a new/next line in the console if the message has more characters than will fit on a single of the terminal.

fwiw, line_len=79 is the default on both windows and linux ime. You would only encounter overflow if you (1) shrunk the terminal from its default width and (2) printed a message that was longer than that shrunken width.

If you really needed to have a progress bar that accounted for a shrunken display, it could be accomplished trivially with Python 3.? and less-trivially with Py2.

I could see depending on this library if the application was client facing and needed to be automagically pretty.

Also, one thing to note is that tqdm only fetches the console width when init'ing a progress bar... if you shrink the terminal while a progress bar is still "in progress," you will encounter the same overflow issue.

[deleted]8 jaar geleden

anhtran8 jaar geleden

I’m using this for progress bar in python http://click.palletsprojects.com/en/5.x/utils/