How to create a spinning command line cursor?

Is there a way to print a spinning cursor in a terminal using Python?

nos

Something like this, assuming your terminal handles \b

import sys
import time

def spinning_cursor():
    while True:
        for cursor in '|/-\\':
            yield cursor

spinner = spinning_cursor()
for _ in range(50):
    sys.stdout.write(next(spinner))
    sys.stdout.flush()
    time.sleep(0.1)
    sys.stdout.write('\b')

Victor Moyseenko

Easy to use API (this will run the spinner in a separate thread):

import sys
import time
import threading

class Spinner:
    busy = False
    delay = 0.1

    @staticmethod
    def spinning_cursor():
        while 1: 
            for cursor in '|/-\\': yield cursor

    def __init__(self, delay=None):
        self.spinner_generator = self.spinning_cursor()
        if delay and float(delay): self.delay = delay

    def spinner_task(self):
        while self.busy:
            sys.stdout.write(next(self.spinner_generator))
            sys.stdout.flush()
            time.sleep(self.delay)
            sys.stdout.write('\b')
            sys.stdout.flush()

    def __enter__(self):
        self.busy = True
        threading.Thread(target=self.spinner_task).start()

    def __exit__(self, exception, value, tb):
        self.busy = False
        time.sleep(self.delay)
        if exception is not None:
            return False

Now use it in a with block anywhere in the code:

with Spinner():
  # ... some long-running operations
  # time.sleep(3)

A nice pythonic way is to use itertools.cycle:

import itertools, sys
spinner = itertools.cycle(['-', '/', '|', '\\'])
while True:
    sys.stdout.write(spinner.next())  # write the next character
    sys.stdout.flush()                # flush stdout buffer (actual character display)
    sys.stdout.write('\b')            # erase the last written char

Also, you might want to use threading to display the spinner during a long function call, as in http://www.interclasse.com/scripts/spin.php

A solution:

import sys
import time

print "processing...\\",
syms = ['\\', '|', '/', '-']
bs = '\b'

for _ in range(10):
    for sym in syms:
        sys.stdout.write("\b%s" % sym)
        sys.stdout.flush()
        time.sleep(.5)

The key is to use the backspace character '\b' and flush stdout.

Sure, it's possible. It's just a question of printing the backspace character (\b) in between the four characters that would make the "cursor" look like it's spinning ( -, \, |, /).

curses module. i'd have a look at the addstr() and addch() functions. Never used it though.

For more advanced console manipulations, on unix you can use the curses python module, and on windows, you can use WConio which provides equivalent functionality of the curses library.

Grab the awesome progressbar module - http://code.google.com/p/python-progressbar/ use RotatingMarker.

#!/usr/bin/env python

import sys

chars = '|/-\\'

for i in xrange(1,1000):
    for c in chars:
        sys.stdout.write(c)
        sys.stdout.write('\b')
        sys.stdout.flush()

CAVEATS: In my experience this doesn't work in all terminals. A more robust way to do this under Unix/Linux, be it more complicated is to use the curses module, which doesn't work under Windows. You probably want to slow it down some how with actual processing that is going on in the background.

import sys
def DrowWaitCursor(self, counter):
    if counter % 4 == 0:
        print("/",end = "")
    elif counter % 4 == 1:
        print("-",end = "")
    elif counter % 4 == 2:
        print("\\",end = "")
    elif counter % 4 == 3:
        print("|",end = "")
    sys.stdout.flush()
    sys.stdout.write('\b')

This can be also another solution using a function with a parameter.

Here ya go - simple and clear.

import sys
import time

idx = 0
cursor = ['|','/','-','\\'] #frames of an animated cursor

while True:
    sys.stdout.write(cursor[idx])
    sys.stdout.write('\b')
    idx = idx + 1

    if idx > 3:
        idx = 0

    time.sleep(.1)

Crude but simple solution:

import sys
import time
cursor = ['|','/','-','\\']
for count in range(0,1000):
  sys.stdout.write('\b{}'.format(cursor[count%4]))
  sys.stdout.flush()
  # replace time.sleep() with some logic
  time.sleep(.1)

There are obvious limitations, but again, crude.

来源：https://stackoverflow.com/questions/4995733/how-to-create-a-spinning-command-line-cursor

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python

command-line-interface

progress