tqdm.write(string) doesn't work well when string has \n in it

[half1red]

Hi,
I'am using tqdm 4.23.4 on python 3.6.3.

I noticed what I think might be an issue when I use tqdm.write with a multiline string.
The two snippets below don't work the same way (the correct behavior I think is the second one) :

from time import sleep
from tqdm import tqdm, trange

def test():
    for x in tqdm(range(30)):
        sleep(0.05)
        
for x in trange(10):
    tqdm.write("\ntest " + str(x))
    test()

from time import sleep
from tqdm import tqdm, trange

def test():
    for x in tqdm(range(30)):
        sleep(0.05)
        
for x in trange(10):
    tqdm.write("")
    tqdm.write("test " + str(x))
    test()

Also, but that may be an other issue, I haven't find a way to have nested progress bars with print between bar that would remain plotted (and not print above all the bars).

[casperdcl]

related: #520 (end != "\n"), #398, #467.

I think the problem here is you don't clear the nested bar or print a newline after it.

You need:

def test():
    for x in tqdm(range(30), leave=False):
        sleep(0.05)

A minimal reproduction of your problem:

from tqdm import trange

for i in trange(10):
    for j in trange(10):
        pass

# print("\n")
print("hello")  # prints on top of last nested bar.

[half1red]

Thanks for looking.
I'm not sure we are speaking about the same issue.
The problem I encountered happens when there is a multiline (\n in it) string in tqdm.write() :

from tqdm import trange

for i in trange(3):
    tqdm.write("task " + str(i) + " started")
    for j in trange(4):
        pass

works.

But with

    tqdm.write("task " + str(i) + " done\nand well started")

doesn't.

However I may have misunderstood your answer. If so I'm sorry.

[casperdcl]

The issue in your new example is the same - the inner trange(4) needs a leave=False.

[half1red]

Actually, putting leave=false delete the inner progress bar, which is a different behavior.
What I thought, is that :

    tqdm.write("task " + str(i) + " done\nand well done")

would behave in the same way that :

    tqdm.write("task " + str(i) + " done")
    tqdm.write("and well done")

My guess is that in the second snippet, the code knows that it has to climb up two lines, in the first one, it thinks only one is enough.

In a second time, but I think it's a clearly different, more complex subject, it would be nice to be able to keep all the inner progress bar (for example to keep the stats) while inserting text between them. This issue is linked I think to #230 :

outer: 78%|███████████ | 2/3 [00:00<00:00, 6189.33it/s]
Starting inner1
inner: 100%|██████████████| 4/4 [00:00<00:00, 164482.51it/s]
Starting inner2
inner: 100%|██████████████| 4/4 [00:00<00:00, 164482.51it/s]
Starting inner3
inner: 80%|██████████ | 4/4 [00:00<00:00, 164482.51it/s]

[casperdcl]

if you want all nested bars to remain, then you can manually position them:

from tqdm import tqdm, trange
from time import sleep


def test(position=None, bar=None):
    if bar is None:
        bar = trange(30, position=position)
    for x in bar:
        sleep(0.05)


N = 10

then either:

for x in trange(N):
    test(position=x + 1)
print('\n' * (N - 1))

or pre-allocate:

bars = [trange(30, position=i +1, desc=str(i + 1)) for i in range(N)]
for x in trange(N):
    #tqdm.write("test")
    #tqdm.write("test"); tqdm.write("foo")
    #tqdm.write("test\nfoo")
    test(bar=bars[x])
print('\n' * (N - 1))

However in both cases tqdm.write() doesn't work well - which is an issue (#230)

[BrandonSmithJ]

Here's a solution:

from tqdm import trange 
import time 

def line_messages(messages):
    for i, m in enumerate(messages, 1):
        trange(1, desc=str(m), position=i, bar_format='{desc}')

n_messages = 2
for i in trange(3):
    line_messages(['iter: %s' % i, 'half: %s' % (i/2)])
    time.sleep(1)

for _ in range(n_messages): print()

Preview:

33%|█████████████████████                                  | 1/3 [00:01<00:02,  1.00s/it]
iter: 1
half: 0.5

You can switch the bar to appear below the messages by changing the position parameters of the two trange declarations (i.e. outer one should be length of messages, inner should start at zero, print n_messages+1 at the end).

The downside is having to print newlines after the overall loop to keep the cursor in the correct place afterwards. Also, haven't tested on windows.