Feature request: string method to_file

[nickeubank]

BPO	26605
Nosy	@vstinner, @serhiy-storchaka

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2016-03-22.07:58:11.741>
created_at = <Date 2016-03-21.17:00:15.303>
labels = ['type-feature', 'invalid', 'expert-IO']
title = 'Feature request: string method `to_file`'
updated_at = <Date 2016-03-22.07:58:11.739>
user = 'https://bugs.python.org/nickeubank'

bugs.python.org fields:

activity = <Date 2016-03-22.07:58:11.739>
actor = 'SilentGhost'
assignee = 'none'
closed = True
closed_date = <Date 2016-03-22.07:58:11.741>
closer = 'SilentGhost'
components = ['IO']
creation = <Date 2016-03-21.17:00:15.303>
creator = 'nickeubank'
dependencies = []
files = []
hgrepos = []
issue_num = 26605
keywords = []
message_count = 6.0
messages = ['262141', '262142', '262143', '262144', '262155', '262169']
nosy_count = 4.0
nosy_names = ['vstinner', 'SilentGhost', 'serhiy.storchaka', 'nickeubank']
pr_nums = []
priority = 'normal'
resolution = 'not a bug'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue26605'
versions = []

[nickeubank]

As a social scientists trying to help other social scientists move from language like R, Stata, and Matlab into Python, one of the behaviors I've found unnecessarily difficult to explain is the "file.open()/file.close()" idiom (or, alternatively, context managers). In normal operating systems, and many high level languages, saving is a one-step operation.

I understand there are situations where an open file handle is useful, but it seems a simple to_file method on strings (essentially wrapping a context-manager) would be really nice, as it would save users from learning this idiom.

Any chance it's feasible? Sadly, I have no real C skills so can't implement myself. :(

[vstinner]

It's easy to implement such function in a module and upload such module to PyPI (ex: "to_file" module :-)).

It's not easy to guess user expectations on such function: text encoding, buffering, etc.

Adding a method to the builtin str type which writes into a file is a no-no.

[serhiy-storchaka]

Such function already exists in the stdlib! But with different order of arguments. See pathlib.Path.write_text().

Personally I'm very skeptical about usefulness of similar functions in the stdlib.

[vstinner]

Oh. I wasn't aware of these pathlib methods.

https://docs.python.org/dev/library/pathlib.html#pathlib.Path.write_bytes

https://docs.python.org/dev/library/pathlib.html#pathlib.Path.write_text

[nickeubank]

Seems like existence of a method in the stdlib (or at least in the pathlib part of the stdlib) suggests issues with text encoding can be overcome.

IMHO I would suggest most people have no idea about that method (I've been doing python for years and this has always been a personal frustration, and I've asked several others for better options and no one had one to offer), and it seems like it would make much more sense as a string method. If someone has a string they want to save to disk, I can't imagine anyone looking in the Path library.

I respect the desire to avoid bloat -- the context manager or open/close idiom has just felt unnecessarily complicated (dare I say unpythonic?) for a common task.

Also, I think it's one that data scientists use a lot when they generate outputs to pull into LaTeX documents.

[SilentGhost]

Those methods were added in 3.5, so no wonder many people would be unaware of them. I would suggest first taking such a proposal to python-ideas, since bug tracker is not a venue for proposing/advocating such sweeping changes to the language.