TGINSIGHT SIMILAR POSTS
Изворен канал @pythonotes · Post #32 · 7 фев.
Скорее всего уже слышали, что складывать строки через + это плохая практика. Падение производительности, и всё такое. Без лишних слов, давайте измерять: from timeit import timeit def t1(): # складываем 10 строк через + из переменной t = 'text' for _ in range(1000): s = t + t + t + t + t + t + t + t + t def t2(): # склеиваем список строк через метод join arr = ['text'] * 10 for _ in range(1000): s = ''.join(arr) def t3(): # складываем через + но не из переменной а непосредственно инлайн объекты for _ in range(1000): s = 'text' + 'text' + 'text' + ... # всего 10 раз Теперь каждую строку склейки запустим по 10М раз >>> timeit(t1, number=10000) 0.21951690399964718 >>> timeit(t2, number=10000) 1.4978306379998685 >>> timeit(t3, number=10000) 0.2213820789993406 Хм, а нам говорили что через "+" это плохо и медленно ))) 😁 Тут стоит учитывать, что речь идёт о склейке множества длинных строк. Давайте изменим условия: def t4(): t = 'text'*100 for _ in range(1000): s = t + t + t + t + t + t + t + t + t def t5(): arr = ['text'*100] * 10 for _ in range(1000): s = ''.join(arr) def t6(): for _ in range(1000): s = 'text'*100 + 'text'*100 + ... # всего 10 раз >>> timeit(t4, number=10000) 12.795130728000004 >>> timeit(t5, number=10000) 2.642637542999182 >>> timeit(t6, number=10000) 0.2184546610005782 Вот, уже другой разговор, сразу видна разница, в среднем в 6 раз. Но погодите, почему последний тест t6() по скорости такой же как и t3()? Ведь строки теперь в 100 раз длиннее! Это вопросы оптимизации кода, какие простые изменения ускоряют или замедляют выполнение программы. Мы столкнулись с примером обхода обращения к переменной. Например, именно так работает директива #define в С++, во время компиляции подставляя значение переменной вместо ссылки на неё. В Python это тоже работает, но часто ли вы сможете встретить такой способ работы со строками? К сожалению, способ почти только теоретический. В целом, тесты показали то, что мы хотели. Делаем выводы самостоятельно. Полный листинг 🌍 #tricks
Пребарај: #smrt
@sgmrt · Post #2401 · 25.07.2025 г., 02:59
Train services on the North-South, East-West, Circle & Thomson-East Coast Lines, and some bus services will be extended on the eve of National Day, 8 Aug 2025 (Fri) (after midnight*). See poster for more info! 🇸🇬*Except Circle Line, due to temporary early closure.#SMRThttps://bit.ly/4o5W1RD - SMRT
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@sgmrt · Post #2289 · 25.03.2025 г., 04:24
Train services on the North-South, East-West, Circle & Thomson-East Coast Lines, and some bus services will be extended for commuters travelling late on the eve of Hari Raya Puasa, 30 Mar 2025 (after midnight). Refer to the poster for more info. #SMRThttps://bit.ly/4lcEuGe - SMRT
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@sgmrt · Post #1773 · 25.08.2023 г., 07:03
Train services on the 🚊 North-South, East-West, Circle & Thomson-East Coast Lines, and some 🚍 bus services will be extended for commuters travelling late during the Formula 1 Grand Prix on 15 - 17 Sep (Fri - Sun). 🏁🏎 See the poster for more info. 👀#SMRThttps://bit.ly/45pBZrD - SMRT
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@sgmrt · Post #1758 · 25.07.2023 г., 02:08
Onward as one!🦁 Train services on the 🚊North-South, East-West, Circle & Thomson-East Coast Lines, and some 🚍bus services will be extended for commuters travelling late on the eve of National Day (8 Aug). 🇸🇬💗 Ref to the poster for more info. 👀#SMRThttps://bit.ly/3O5oUfJ - SMRT
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@sgmrt · Post #2406 · 29.07.2025 г., 02:44
Train services on the 🚆 North-South, East-West, Circle & Thomson-East Coast Lines, and some 🚍 bus services will be extended for commuters travelling late on the eve of National Day, 8 Aug 2025 (Fri). 🇸🇬Please refer to the poster for more info. 👀#SMRT#AllAboutTrainshttps://bit.ly/4lTHYxg - SMRT
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@sgmrt · Post #2405 · 29.07.2025 г., 02:39
Train services on the 🚆 North-South, East-West, Circle & Thomson-East Coast Lines, and some 🚍 bus services will be extended for commuters travelling late on the eve of National Day, 8 Aug 2025 (Fri). 🇸🇬Please refer to the poster for more info. 👀#SMRT#AllAboutTrains - SMRT
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@sgmrt · Post #2354 · 26.05.2025 г., 09:04
Train services on the North-South, East-West, Circle & Thomson-East Coast Lines, and some bus services will be extended for commuters travelling late on the eve of Hari Raya Haji, 6 Jun 2025 (Fri) (after midnight). Refer to the poster for more info. #SMRT#AllAboutTrainshttps://bit.ly/4kcRGdi - SMRT
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@sgmrt · Post #2334 · 06.05.2025 г., 09:59
Train services on the North-South, East-West, Circle & Thomson-East Coast Lines, and some bus services will be extended for commuters travelling late on the eve of Vesak Day, 11 May 2025 (Sun) (after midnight). Refer to the poster for more info. #SMRT#AllAboutTrainshttps://bit.ly/4k8NOtm - SMRT
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@sgmrt · Post #2230 · 22.01.2025 г., 03:44
Train services on the North-South, East-West, Circle & Thomson-East Coast Lines, and some bus services will be extended for commuters travelling late on the eve of Chinese New Year, 28 Jan (after midnight). See poster for more info.🧧#SMRT#AllAboutTrains#AllAboutBuseshttps://bit.ly/4g6JEzO - SMRT
@sgmrt · Post #2157 · 17.10.2024 г., 03:09
Train services on NSEWL, CCL, TEL and some bus services will be extended for commuters travelling late on the eve of Deepavali, 30 Oct 2024 (Wed). 🪔 See the poster for more info! 👀#SMRT#AllAboutTrains#AllAboutBuseshttps://bit.ly/4dKOXni - SMRT
@sgmrt · Post #1947 · 31.05.2024 г., 02:09
Train services on the North-South, East-West, Circle & Thomson-East Coast Lines, and some bus services will be extended for commuters travelling late on the eve of Hari Raya Haji, 16 Jun 2024 (after midnight). Ref to the poster for more info. #SMRT#AllAboutTrains#AllAboutBuseshttps://bit.ly/4bWEkx9 - SMRT
@sgmrt · Post #1902 · 04.04.2024 г., 02:29
Train services on North-South, East-West, Circle & Thomson-East Coast Lines, and some bus services will be extended for commuters travelling late on eve of Hari Raya Puasa, 9 Apr 2024 (after midnight). Ref to the poster for more info. #SMRT#AllAboutTrains#AllAboutBuseshttps://bit.ly/3vLtQRF - SMRT