Alex summarized well but, surprisingly, was too succinct. First, let me reiterate the main points in Alex’s post: The default implementation is useless (it’s hard to think of one which wouldn’t be, but yeah) __repr__ goal is to be unambiguous __str__ goal is to be readable Container’s __str__ uses contained objects’ __repr__ Default implementation is … Read more
os.listdir() returns everything inside a directory — including both files and directories. os.path‘s isfile() can be used to only list files: from os import listdir from os.path import isfile, join onlyfiles = [f for f in listdir(mypath) if isfile(join(mypath, f))] Alternatively, os.walk() yields two lists for each directory it visits — one for files and … Read more
DataFrame.iterrows is a generator which yields both the index and row (as a Series): import pandas as pd df = pd.DataFrame({‘c1’: [10, 11, 12], ‘c2’: [100, 110, 120]}) df = df.reset_index() # make sure indexes pair with number of rows for index, row in df.iterrows(): print(row[‘c1’], row[‘c2’]) 10 100 11 110 12 120
From Python Documentation: An except clause may name multiple exceptions as a parenthesized tuple, for example except (IDontLikeYouException, YouAreBeingMeanException) as e: pass Or, for Python 2 only: except (IDontLikeYouException, YouAreBeingMeanException), e: pass Separating the exception from the variable with a comma will still work in Python 2.6 and 2.7, but is now deprecated and does … Read more
Use datetime: >>> import datetime >>> now = datetime.datetime.now() >>> now datetime.datetime(2009, 1, 6, 15, 8, 24, 78915) >>> print(now) 2009-01-06 15:08:24.789150 For just the clock time without the date: >>> now.time() datetime.time(15, 8, 24, 78915) >>> print(now.time()) 15:08:24.789150 To save typing, you can import the datetime object from the datetime module: >>> from datetime … Read more
Use the in operator: if “blah” not in somestring: continue
You can use a global variable within other functions by declaring it as global within each function that assigns a value to it: globvar = 0 def set_globvar_to_one(): global globvar # Needed to modify global copy of globvar globvar = 1 def print_globvar(): print(globvar) # No need for global declaration to read value of globvar … Read more