Convert and Iterate clear solution for Digits Multiplication by bryukh - python coding challenges

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Convert and Iterate solution in Clear category for Digits Multiplication by bryukh

def checkio(number):
    """
    Convert into the string and iterate.
    """
    res = 1
    for d in str(number):
        res *= int(d) if int(d) else 1
    return res

Feb. 20, 2014

Comments:

matlex_e92656adfca8491aac435b0 on Feb. 22, 2014, 7:31 p.m.
Nice implementation. By the way - you could did it without "else 1". I think it's not nessesary.

bryukh on Feb. 22, 2014, 10:37 p.m.
Could you explain it more careful?

matlex_e92656adfca8491aac435b0 on Feb. 23, 2014, 11:20 a.m.
I mean there's no need to use "else". Sorry for confusing :) Just enough: <pre class='brush: python'>def checkio(number): """ Convert into the string and iterate. """ res = 1 for d in str(number): if int(d): res *= int(d) return res </pre>

bryukh on Feb. 23, 2014, 8:21 p.m.
Oh, got it.

Czarinov on July 30, 2015, 9:11 p.m.
Doesn't work without "else 1"

2chaosman on Aug. 25, 2015, 9:57 a.m.
Works fine without "else 1"

Czarinov on Aug. 25, 2015, 2:23 p.m.
<pre class='brush: python'>def checkio(number): res = 1 for d in str(number): res *= int(d) if int(d) return res SyntaxError: invalid syntax (<MYCODE>, line 4) ?, ? </pre>

Czarinov on Aug. 25, 2015, 2:24 p.m.
Nevermind, I just thought putting 'else 1' away, not rewriting the code... didn't notice. Sorry. too bad stuff doesn't work like: [action] if [condition]

hanpari on Feb. 27, 2014, 8:13 p.m.
Well, similar to me, but I tried to avoid double calling of int(). I thought it is better to call function rather once than twice. Am I correct? Or it doesnt matter? I mean generally, not in this easy tasks.

bryukh on Feb. 27, 2014, 8:41 p.m.
<blockquote> Am I correct? Or it doesnt matter? </blockquote> Yes, but this is micro optimisation.

hanpari on Feb. 28, 2014, 5:04 p.m.
Thanks

Reb_Sadran on March 19, 2014, 11:57 a.m.
ah if ind(d) is a clever one

TrexxaByte on Jan. 29, 2022, 10:10 p.m.
See... this is the type of things I see that I don't understand... if d is an integer? Is that what it's doing? If so, how the hell is he avoiding the ZERO?! I assume by setting res = 1 ... but I don't see how? It works, though... I'm gonna debug it in IDLE and see wth... I'm seriously baffled lol

lxf42 on Feb. 18, 2022, 12:46 p.m.
if int(d) actually tests if d is not equal to zero, 0 == False, all non-zero == True to highlight when you convert to bool: <pre class='brush: python'>>>> bool(0) False >>> bool(1) True >>> bool(8) True </pre>

zver1zver2 on July 6, 2014, 9:11 a.m.
good code

UndeadMonkey on Oct. 16, 2014, 7:52 p.m.
Very clear and succinct; I like it!

lesenv on Nov. 29, 2014, 11:22 p.m.
i wanted to avoid the init of res = 1, so i found the functools.reduce. but now i see that your code i so much readable. thumps up!

marshall.zheng on Dec. 25, 2014, 4:55 a.m.
wondering whether there is one-line solution...

Papygorgio on April 30, 2015, 10:17 p.m.
You could do it this way <pre class='brush: python'>checkio = lambda n: eval("*".join(i for i in str(n) if i != '0')) </pre> Not my work so if you want more explanations go to the creative section :)

johnoommen on Dec. 29, 2014, 12:44 p.m.
nice sol.

Pyth0n2 on Jan. 8, 2015, 6:12 a.m.
oh, I wasted a line doing this: <pre class='brush: python'>number = str(number) </pre> When I could have just changed it to str() in the for loop statement. nice.

Freiling on July 2, 2017, 9:16 p.m.
I did too. Would anyone care to tell whether one way is more resource-conservative? I would think that the above creates an extra line of code but saves us from redoing an operation needlessly.

egemen on Jan. 30, 2015, 5:57 p.m.
I think the "else" part should be (0), because that's the number we don't want to multiply.

andraz.gruden.90 on Feb. 16, 2015, 8:37 p.m.
i have made the same but check this out. I have converted, joined string with "*" replaced "0", "1" and eval the string :) But yours is clean and likable. )

jetuuuu on March 5, 2015, 9:17 a.m.
Same ;)

xero on June 25, 2015, 8:20 a.m.
Thank you. I didn't know there could be condition statement with *= statement. Learned something.

Wuzequan on July 1, 2015, 8:43 a.m.
very clear

Jerry_Murphy on Aug. 1, 2015, 12:02 a.m.
Can some one explain the int(d) else 1 part please?

bryukh on Aug. 3, 2015, 7:38 a.m.
if d == "0", then int(d) == 0, so "if int(d):" works only if d != "0".

leggewie on May 24, 2021, 7:39 p.m.
This is actually not correct. <pre class='brush: python'>In [211]: d=0 In [212]: type(d) Out[212]: int </pre> Maybe this changed?

leggewie on May 24, 2021, 7:44 p.m.
I recant ;-) <pre class='brush: python'>In [214]: type("0") Out[214]: str In [217]: bool(int("0")) Out[217]: False In [218]: bool(int("1")) Out[218]: True In [219]: bool(int("2")) Out[219]: True </pre> VERY clever coding!

TrexxaByte on Jan. 29, 2022, 10:19 p.m.
Woah woah woah... WTF?! I was dumbfounded trying to figure out how he skipped over the zeros... trying to see what I was missing... debugged his code in IDLE, and yeah, I ran a check on zero, but... I did: <pre class='brush: python'>int(0) int('0') </pre> Silly me... but God bless you, man... you saved me from driving myself insane LOL Thanks a million! Legit, thank you lol.

saghirmhussain on Aug. 12, 2015, 5:44 a.m.
Sick! I'm a beginner and I have been able to reduce my code from about 10 lines to 4 with this.

andrewg12 on Sept. 6, 2015, 3:38 p.m.
so for d in str(number) turns the number into a string and sets up a for loop, then inside the for loop you use your res[product storage] to multiply it by int d, each of the tens places, if int(d) > 0, else 1? return product. What is the else 1 here for? I dont really understand that part. I also dount understand how you got around the use of the colon in the if statement. Is there a technique I don't know yet going on here?

TrexxaByte on Jan. 29, 2022, 10:26 p.m.
It's sneaky... tricky little trick... look at the comment above yours. Zero returns FALSE when tested as integer in a boolean! I didn't realize that... until today. I think it's the ONLY number that does that, too! Even negative numbers return True... that's wild. Look: <pre class='brush: python'>bool(int('0')) False bool(int(0)) False </pre>

maksimkovnir on Jan. 11, 2016, 7:02 a.m.
So clear, short) I like it. And it work's without "else". :)

Aunmag on April 3, 2016, 8:36 a.m.
The best!)

laetrid on April 5, 2016, 7:30 a.m.
And if the number is 0 or 0000 for example, return should be 0 I believe.

leggewie on May 24, 2021, 7:41 p.m.
not according to the instructions as of 2021 at least <ul> <li>number will never be 0 or 0000</li> <li>any digit 0 from within number is to be dropped.</li> </ul> Maybe the instructions changed? I understand I'm responding to an ancient comment.

ljy95135 on May 24, 2016, 9:11 a.m.
Use twice int can save some lines, so there are many choices. And there is the charm of coding. :)

Qais on Sept. 29, 2016, 12:08 p.m.
def checkio(number): result = 1 # store final result while number > 0: number, rem = divmod(number, 10) if rem > 0: # to pass zero's value result *= rem return result this solution faster. I check it with python %time.

bryukh on Sept. 29, 2016, 12:52 p.m.
Oh. Why do you think I had been trying to make "speed" solution? It's "Clear" category. If you want speed, then use noPython. Or PyPy.

Qais on Sept. 29, 2016, 1:07 p.m.
it is just another solution, regard to performance. be easy :)

bryukh on Sept. 29, 2016, 1:24 p.m.
<blockquote> it is just another solution, regard to performance </blockquote> You can publish your solution in the "Speed" category instead here. I don't see what for you have posted it here. I know how to make "speed" solution (even faster than yours). <blockquote> be easy :) </blockquote> be non-arrogant. :-)

Qais on Sept. 29, 2016, 8:02 p.m.
actually, I do not know there are multi categories, I am deleted it.

hugoboss on Aug. 8, 2018, 12:53 p.m.
I can this way so... What you say about recursion: 'checkio = lambda n: (n%10 or 1)*checkio(n//10) if n else 1' from yun_zynb??? my mind is blown :((

z.a.timur on June 6, 2019, 6:30 a.m.
Cool didnt knew int(0)doesnt count as integer

hanpari on June 6, 2019, 3:15 p.m.
It is not int(0) but int("0") Furthermore, because int("0") == 0 there is the conditional expression in which 0 is replaced by 1. <a href="https://stackoverflow.com/questions/394809/does-python-have-a-ternary-conditional-operator">https://stackoverflow.com/questions/394809/does-python-have-a-ternary-conditional-operator</a>

TrexxaByte on Jan. 29, 2022, 10:28 p.m.
Me either! I feel kind of dumb not knowing that all this time... until TODAY! LOL :P I guess because you would expect an error if you did int(0) but there isn't... Yet it comes back False either way... string OR numeric, it comes back False when tested as integer! @ . @

DragonMachinations on Aug. 6, 2019, 3:41 a.m.
Nicely done. I wish I'd thought of condensing it onto one line inside the for loop like that.

sao3505 on Oct. 3, 2019, 7:17 a.m.
clean and nice

jiizzyy on Jan. 31, 2020, 1:23 p.m.
It would be cool if we could convert d into integer in the for loop declaration. Something like this: <pre class='brush: python'>res = 1 for int(d) in str(number): res *= d if d return res </pre>

RafalBlaczkowski on Feb. 10, 2020, 3:14 p.m.
the best solution ;)

lifeshow30s on June 19, 2020, 3:32 a.m.
convert to string to iterate, back to digit for mutiplying.

Safwan_Samsudeen on Nov. 14, 2020, 4:31 a.m.
Great solution. But I used `math.prod([int(char) for char in str(number) if char != '0'])`. Is there any disadvantages in that?

TrexxaByte on Jan. 29, 2022, 10:41 p.m.
Me too... the task even suggested using it. The disadvantage would be having to import the module... BUT, since we only use ONE function from the math module, I would advise/suggest to make sure you do: <pre class='brush: python'>from math import prod </pre> rather than: <pre class='brush: python'>import math </pre> ... I always try to limit imports since some modules can be quite a large package... cutting the import down to just certain functions (just one in this case) is a practice I consider pretty vital or important. :) EDIT Unrelated... but one other thing came to mind, along the lines of "best practices" in your coding... It's actually something I read about "Pythonic" guidelines or something? I honestly don't like to adhere to some of the standards and practices they mention, and one of the expressions I reluctantly stopped using because of those "standards" is in your code :P "Pythonic" or whatever advises and/or suggests avoiding the use of the does NOT equal expression... <pre class='brush: python'>if char != '0' </pre> It explained why or the reason behind it but I can't remember LOL. If it wasn't supposed to be used, it wouldn't be a valid expression anyway, right? :P But wanted to mention that ... long post, but honestly, I can tell you're looking for feedback, because I do the same .. a LOT... and I just wanted to give advice, guidance, or knowledge the way I wish someone would do on MY threads LOL I need to just take a course... ugh... can't afford that, though :)

.pondering_ on April 28, 2024, 1:27 a.m.
This solution seems so simple, love the if int(d) and thanks for sharing!

Strings and Integers

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