using method as function in python

Question

Say I have a list of strings, and I want to filter out all non-upper case strings. Is there a simpler way than doing filter(lambda x: x.isupper(), list)?

@The Communist Duck: why is boilerplate bad? It's not a big deal, but it is annoying. — CromTheDestroyer
– CromTheDestroyer, Commented Jun 6, 2011 at 17:34
You could define a function to do this, but it will still take one line to invoke it. — Eric Wilson
– Eric Wilson, Commented Jun 6, 2011 at 17:38
@CromTheDestroyer: What part is "boilerplate"? Can you be more specific on what you object to? — S.Lott
– S.Lott, Commented Jun 6, 2011 at 17:38
@S.Lott: the lambda is. In my head I was contrasting it to the case where a function is passed in. Cosmologicon's answer is what I was looking for. — CromTheDestroyer
– CromTheDestroyer, Commented Jun 6, 2011 at 17:41
@CromTheDestroyer: The lambda is as much boilerplate as the word filter. Only in the most trivial of cases could is be considered "boilerplate". lambda x: x.isupper() and x not in ('Z','z') would demonstrate that the lambda is essential syntax. — S.Lott
– S.Lott, Commented Jun 6, 2011 at 18:55

Cosmologicon · Accepted Answer · 2011-06-06 17:38:25Z

10

While I would prefer a list comprehension, this seems to be what you're looking for:

filter(str.isupper, list)

answered Jun 6, 2011 at 17:38

Cosmologicon

2,1873 gold badges16 silver badges18 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Jess Over a year ago

If the function already works as-is, why bother with the comprehension?

Cosmologicon Over a year ago

You're right, this is a perfectly fine use of filter. I hardly ever use it is all. I just like comprehensions.

senderle Over a year ago

Clearly you're using list as a metasyntactic variable here, but if you weren't, I would have to point out that using list this way masks a built-in ;).

manji · Accepted Answer · 2011-06-06 17:41:11Z

5

uppers = [s for s in list if s.isupper()]

edited Jun 6, 2011 at 17:41

answered Jun 6, 2011 at 17:35

manji

48k5 gold badges98 silver badges104 bronze badges

3 Comments

Steven Rumbalski Over a year ago

I think this would be easier to read with s as the variable name instead of i.

CromTheDestroyer Over a year ago

I'm sorry, I should have clarified that the question was about passing methods into functions as functions, not solving this trivial problem.

manji Over a year ago

ok, no problem. (if you re-read your question you will see that it's nearly impossible to understand that).

Collectives™ on Stack Overflow

using method as function in python

2 Answers 2

3 Comments

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related