Generator Expression

Mozaikszó
Mozaikszó a(z) Python kurzusban 
def abbreviate(to_abbreviate):
    phrase = to_abbreviate.replace("-", " ").replace("_", " ").upper().split()
    
    # Note the lack of square brackets around the comprehension.
    return "".join(word[0] for word in phrase)
  • This approach begins by using str.replace() on to_abbreviate to convert non-letter characters such as - and _ into spaces.
  • The phrase is then upper-cased by calling str.upper().
  • Finally, the phrase is turned into a list of words by calling str.split().

The three methods above are all chained together, with each method operating on the output of the method before it in the "chain". This works because both replace() and upper() operate on strings (as they are str methods) and return strings. If split() was called first, replace() and upper() would fail, since they cannot operate on the list returned by split().

Note

re.findall() or re.finditer() can also be used to clean to_abbreviate. These two methods from the re module will return a list or a lazy iterator of results, respectively. As of this writing, both of these methods benchmark slower than using str.replace() for cleaning.

A generator-expression is then used to iterate through the phrase and select the first letters of each word via bracket notation.

Generator expressions are short-form generators — lazy iterators that produce their values on demand, instead of saving them to memory. This generator expression is consumed by str.join(), which joins the generated letters together using an empty string. Other "separator" strings can be used with str.join() — see string-methods for some additional examples. Since the generator expression and join() are fairly succinct, they are put directly on the return line, rather than assigning and returning an intermediate variable for the acronym.

In benchmarks, this solution was surprisingly slower than the list comprehension version. This article from Oscar Alsing briefly explains why.

23. Sep 2026 · Hasznosnak találtad?

További megközelítések a(z) Mozaikszó feladathoz a(z) Python kurzusban

További módok, ahogy közösségünk megoldotta ezt a feladatot
from functools import reduce

def abbreviate(to_abbreviate):
    phrase = to_abbreviate.replace("-", " ").replace("_", " ").upper().split()

    return reduce(lambda start, word: start + word[0], phrase, "")
Functools Reduce

Use functools.reduce() to form an acronym from text cleaned using str.replace(). 

def abbreviate(to_abbreviate):
    phrase = to_abbreviate.replace("-", " ").replace("_", " ").upper().split()

    return "".join([word[0] for word in phrase])
List Comprehension

Use a list comprehension with str.join() to form an acronym from text cleaned using str.replace(). 

def abbreviate(to_abbreviate):
    phrase = to_abbreviate.replace("-", " ").replace("_", " ").upper().split()
    acronym = ""

    for word in phrase:
        acronym += word[0]

    return acronym
Loop

Use str.replace() to clean the input string and a loop with string concatenation to form the acronym. 

def abbreviate(to_abbreviate):
    phrase = to_abbreviate.replace("-", " ").replace("_", " ").upper().split()
    
    return "".join(map(lambda word: word[0], phrase))
Map Built-in

Use the built-in map() function to form an acronym after cleaning the input string with str.replace(). 

import re

def abbreviate(phrase):
    removed = re.findall(r"[a-zA-Z']+", phrase)

    return "".join(word[0] for word in removed).upper()
Regex join

Use regex to clean the input string and form the acronym with str.join(). 

import re

def abbreviate_regex_sub(to_abbreviate):
    pattern = re.compile(r"(?<!_)\B[\w']+|[ ,\-_]")

    return re.sub(pattern, "", to_abbreviate.upper())
Regex Sub

Use re.sub() to clean the input string and create the acronym in one step. 

VALID_CHARS = {" ", "-"} | set(ascii_letters)

def abbreviate(to_abbreviate):
    to_abbreviate = "".join(" " if char == "-" else char
                            for char in to_abbreviate
                            if char in VALID_CHARS)

    return "".join(word[0] for word in to_abbreviate.split()).upper()
Double Generator Expression

Use generator expressions for both cleaning and joining the input.