Creating Anagram Detector

I'm having trouble getting this anagram function to work. The aim is for the function to take 2 strings abc and cba, convert them into a list; sort them in to alphabetical order,

Solution 1:

Your problem is that you can't call String.sort(). Try changing:

x1 = x.sort()
y1 = y.sort()

to:

x1 = sorted(x)
y1 = sorted(y)

Solution 2:

The specific issue

x.sort() works in-place if x is a list. This means the sort method changes the objects internal representation. It also returns None which is the reason why it doesn't work as intended.

If x is a string, there is no .sort() method as strings are immutable.

I recommend to use the sorted() function instead, which returns the sorted string.

The more general issues

There are two more general issues:

1. Runtime: This is an O(log(n) * n) solution
2. Unicode modifiers and compound glyphs
3. Print: You print the value, but instead you should return the result. How would you test your code?

Unicode modifiers

Lets say you wrote the function more compact:

defis_anagram(a: str, b: str) -> bool:
    returnsorted(a) == sorted(b)

This works fine for normal characters, but fails for compound glyphs. For example, the thumbsup / thumbsdown emoji can be modified to have different colors. The change in color is actually a second unicode "character" which gives the skin tone. The modifier and the previous character belong together, but sorted just looks at the code points. Which results in this:

>>> is_anagram("👍👎🏿", "👎👍🏿")
True# <-- This should be False!

Sublime Text shows the actual code points:

You can easily fix this by using the grapheme package:

from grapheme import graphemes
defis_anagram(a: str, b: str) -> bool:
    returnsorted(graphemes(a)) == sorted(graphemes(b))

Runtime

You can get O(n) runtime if you don't sort, but instead count characters:

from collections import Counter
from grapheme import grahemes

defis_anagram(a: str, b: str) -> bool:
    returnnot (Counter(grapheme(a)) - Counter(grapheme(b)))

Solution 3:

you cannot call .sort() on a string, nor should you be cause that is actually a method that sorts a list in place and will not return anything. instead, use sorted(x)

>>> defanagram(str1, str2):
    x1 = sorted(str1)
    y1 = sorted(str2)

    if (x1) == (y1):
        print("Anagram is True")
    else:
        print("Anagram is False")


>>> anagram('abc','bca')
Anagram isTrue