CODEWITHSUNDEEP
pythontqdm
yujaiyu
yujaiyu

Reputation: 9003

How to construct a trange and use it later?

I want to construct trange but to use it later. For example:

from tqdm import trange

if progress:
    r = trange(10)
else:
    r = range(10)

for _ in r:
    # do something

However, at the construction time, trange will print an empty progress line (with 0%), and later it will print a new one (as expected).

How to avoid this?

Obviously, there are tricks to work around this, for example:

for _ in trange(10) if progress else range(10):
    # do something

or what @BatWannaBe suggests below.

However, I would prefer something cleaner. Why does trange print anything at construction time, in the first place?

Upvotes: 1

Views: 11378

Answers (2)

Coder
Coder

Reputation: 1254

Is this cleaner?

from tqdm import trange

progress = False  # We should see no tqdm now

if progress:
    r = lambda n: trange(n)
else:
    r = lambda n: range(n)

for _ in r(10):
    # do something
    ...

Upvotes: 0

BatWannaBe
BatWannaBe

Reputation: 4510

It seems like the progress bar shows up whenever a tqdm.tqdm instance is constructed, which trange does: trange(n) is shorthand for tqdm.tqdm(range(n)). I'm not sure if there's any way around that. However, you can delay the construction by keeping a temporary range(n) object.

from tqdm import tqdm

r = range(10)

if progress:
    for _ in tqdm(r):
        # do something
else:
    for _ in r:
        # do something

If progress is True/False, you could reduce the duplicated code with this trick treating False as 0 and True as 1:

maybetqdm = [lambda x:x, tqdm] # lambda x:x is function that does nothing

for _ in maybetqdm[progress](r):
    # do something

Upvotes: 1

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