Cli: fence-posting problem

[LecrisUT]

• I have marked all applicable categories:
  • documentation request (i.e. "X is missing from the documentation." If instead I want to ask "how to use X?" I understand StackOverflow#tqdm is more appropriate)
  • new feature request
• I have visited the source website, and in particular
  read the known issues
• I have searched through the issue tracker for duplicates
• I have mentioned version numbers, operating system and
  environment, where applicable:

  import tqdm, sys
  print(tqdm.__version__, sys.version, sys.platform)

Description

In order to first initialize the tqdm progress bar in the shell environment there must be something output so that the tqdm starts to output to console. But if the commands in the loop are slow, it would not create the initial progress bar for a while.

Suggestion

There could be 2 ways around it

• have tqdm cli run once outside the loop with or without stdin but with the same format to create the initial progress-bar (fencepost issue)
• option to parse stdin through regex to trigger an increment or not, e.g. r"Done (?P<it>\d+)/(?P<total>\d+)". Note the group names that can be used to extract other data for tqdm

Consideration

This approach would not be efficient, but the usecase here is especially for slow processes that are needed to be monitored, so this would not be an issue.