Python_peeves

Python Peeves

This post lists examples of python code or style with explanations as to why they seem peevish to me. Here we go…

#1. (Mis)print The print function earns the first spot for it is apparently mishandled even by “people paid to code”.

1.1 Formating percentages: multiplying by 100 not needed!

I’ve seen this too many times:

print(f'formated percentage: {pct*100:.2f}%')

The percentage formating parameter % can take care of that:

print(f'formated percentage: {pct:.2%}')

1.2 Concatenation inside print:

Apparently, many developers have a hidden typist in them. I’ve seen this a lot from coders who apparently do not know that the comma-separated items are concatenated with a space, the default separator:

print('some text ' + str(value1) + ' other text ' + str(value2))

This simpler statement yields the same output:

# removed spaces around strings & after commas to show they're not needed:
print('some text',value1,'other text',value2) 

Output:

some text 1 other text 2

This works because of two parameters and their default values: sep=' ' and end='\n'.