CLN: Remove type definitions from pandas.compat

[jschendel]

• xref CLN: remove PY2 #25725
• tests added / passed
• passes git diff upstream/master -u -- "*.py" | flake8 --diff

Removes the following:

• string_types
• text_types
• binary_types
• string_and_binary_types
• strlen
  • only used once and in PY3 is equivalent to len, so just directly called len
• east_asian_len
  • only called by EastAsianTextAdjustment.len in pandas/io/formats/format.py
  • directly implemented as EastAsianTextAdjustment.len instead

[jschendel]

Note that these changes now reduce the is_string_like function in pandas/core/dtypes/inference.py to simply be isinstance(obj, str):

pandas/pandas/core/dtypes/inference.py

Lines 69 to 90 in 6701e71

	def is_string_like(obj):
	"""
	Check if the object is a string.
	Parameters
	----------
	obj : The object to check
	Examples
	--------
	>>> is_string_like("foo")
	True
	>>> is_string_like(1)
	False
	Returns
	-------
	is_str_like : bool
	Whether `obj` is a string or not.
	"""
	return isinstance(obj, str)

Does it make sense to deprecate is_string_like and convert all existing references to the isinstance check as a followup?

[WillAyd]

I would be +1 on replacing that function with isinstance checks - if anything I think it will make static code analysis cleaner

[codecov]

Codecov Report

Merging #25903 into master will increase coverage by 0.02%.
The diff coverage is 94.14%.

@@            Coverage Diff             @@
##           master   #25903      +/-   ##
==========================================
+ Coverage   91.53%   91.56%   +0.02%     
==========================================
  Files         175      175              
  Lines       52808    52747      -61     
==========================================
- Hits        48338    48297      -41     
+ Misses       4470     4450      -20

Flag	Coverage Δ
#multiple	90.12% <92.18%> (+0.02%)	⬆️
#single	41.8% <41.79%> (-0.03%)	⬇️

Impacted Files	Coverage Δ
pandas/io/parquet.py	84.46% <ø> (-0.15%)	⬇️
pandas/compat/pickle_compat.py	75.3% <ø> (-0.31%)	⬇️
pandas/io/formats/latex.py	100% <ø> (ø)	⬆️
pandas/core/computation/scope.py	93.06% <ø> (ø)	⬆️
pandas/plotting/_timeseries.py	65.28% <0%> (-0.18%)	⬇️
pandas/core/panel.py	35.53% <0%> (ø)	⬆️
pandas/core/computation/engines.py	88.52% <0%> (-0.19%)	⬇️
pandas/io/json/normalize.py	96.93% <100%> (ø)	⬆️
pandas/plotting/_style.py	77.17% <100%> (-0.25%)	⬇️
pandas/util/testing.py	90.73% <100%> (+0.27%)	⬆️
... and 68 more

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[codecov]

Codecov Report

Merging #25903 into master will increase coverage by 0.01%.
The diff coverage is 94.86%.

@@            Coverage Diff             @@
##           master   #25903      +/-   ##
==========================================
+ Coverage   91.77%   91.79%   +0.01%     
==========================================
  Files         175      175              
  Lines       52606    52538      -68     
==========================================
- Hits        48280    48228      -52     
+ Misses       4326     4310      -16

Flag	Coverage Δ
#multiple	90.35% <93.28%> (+0.02%)	⬆️
#single	41.88% <41.89%> (-0.1%)	⬇️

Impacted Files	Coverage Δ
pandas/io/parquet.py	84.46% <ø> (-0.15%)	⬇️
pandas/compat/pickle_compat.py	69.13% <ø> (-0.38%)	⬇️
pandas/io/formats/latex.py	100% <ø> (ø)	⬆️
pandas/core/computation/scope.py	93.06% <ø> (ø)	⬆️
pandas/plotting/_timeseries.py	65.28% <0%> (-0.18%)	⬇️
pandas/core/panel.py	35.53% <0%> (ø)	⬆️
pandas/core/computation/engines.py	88.52% <0%> (-0.19%)	⬇️
pandas/io/json/normalize.py	96.93% <100%> (ø)	⬆️
pandas/plotting/_style.py	77.17% <100%> (-0.25%)	⬇️
pandas/util/testing.py	90.63% <100%> (+0.17%)	⬆️
... and 68 more

---

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[WillAyd]

lgtm - over to you @jreback

[WillAyd]

Just thinking out loud but wondering if we should make something to fuse type, np.dtype and str. Would certainly help out in some of the typing things we have going on

[jreback]

can merge master. sorry i think merged something else and causes conflicts.

[jreback]

thanks @jschendel