Why is second argument not detected in Python Coroutines?

Question

I have modified some code from Coroutines as follows:

def grep(p1, p2):
    print("Searching for", p1 ,"and", p2)
    while True:
        line = (yield)
        if (p1 or p2) in line:
            print(line)

search = grep('love', 'woman')
next(search)
search.send("I love you")
search.send("Don't you love me?")
search.send("I love coroutines instead!")   
search.send("Beatiful woman")

Output:

Searching for love and woman
I love you
Don't you love me?
I love coroutines instead!

Second argument "woman" is not recognized in the last search. Why is that?

If you type `a = "love" and b = ''woman"` in python interpreter and if we perform `a or b` it returns `love` — Abdul Niyas P M, Feb 17 '18 at 08:45
Also relevant: https://stackoverflow.com/questions/3389574/check-if-multiple-strings-exist-in-another-string — Ilja Everilä, Feb 17 '18 at 11:35

Omar Einea · Accepted Answer · 2018-02-17T12:42:21.550

3

Your condition should be like this:

if p1 in line or p2 in line:

because (p1 or p2) would return p1 as long as there's something in it.
so your current condition always evaluates to if p1 in line:

edited Feb 17 '18 at 12:42

answered Feb 17 '18 at 08:42

Omar Einea

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score 0 · Answer 2 · answered Feb 17 '18 at 11:44

Because your code condition is either of two arguments(p1 or p2) matches it return only p1 thats why it donot return the last send function result. Now try this code .

Also I am attach the screenshot of output of the code.

 def grep(p1, p2):
        print("Searching for", p1 ,"and", p2)
        while True:
            line = (yield)
            if (p1) in line:
                print(line)
            if (p2) in line:
                print(line)

    search = grep('love', 'woman')
    next(search)
    search.send("I love you")
    search.send("Don't you love me?")
    search.send("I love coroutines instead!")   
    search.send("beautiful woman")

Why is second argument not detected in Python Coroutines?

2 Answers2