Here’s one: deleting an entry from a dictionary, but only if it exists. Because del dict[key] will raise KeyError if there is no such entry. So you have to do an explicit check first, the long way: if key in dict : del dict[key] ♯end if but there is a shorter way: dict.pop(key, None)
@318th2 жыл бұрын
Thats a clever one
@ghaythghannouchi34272 жыл бұрын
You can use the dict.get(key) If the key doesn't exist it will return None so the code will be like this If dict.get(key) is not None: del dict[key]
@ad_cfc2 жыл бұрын
@@ghaythghannouchi3427 Or "del dict[key] if dict.get(key) else None"
@NikoKun2 жыл бұрын
A couple of my favorite one-liners: # Remove whatever punctuation you want from an input string: outputStr = "".join(ch for ch in inputStr if ch not in ",.?!'") # Return the Ordinal Suffix for day of the month: 1st, 2nd, 3rd, 4th, etc. def ordsuf(day): return ["","st","nd","rd"][day%10] if day%10 in [1,2,3] and day not in [11,12,13] else "th" # alternative that returns both number and suffix together, takes string, gives string: def orday(day): return day+'th' if int(day) in [11,12,13] else day+{1:'st',2:'nd',3:'rd'}.get(int(day)%10,'th')
@jatindua58662 жыл бұрын
Could you please explain the second one? I'm unable to get it
@NikoKun2 жыл бұрын
@@jatindua5866 Sure, that one is a bit tricky to explain, but I'll try. It defines a function called ordinal, which when provided a integer, usually a day from 1-31, the function returns a string of either "st", "nd", "rd", or "th". The part after return is a list containing those, but in a specific order, because we then use [day%10] as an index to determine which of those 4 strings is returned. %10 divides the number by 10, but ignores the result and gets the remainder left over instead, so 23 just becomes 3. The next part, if day%10 in [1,2,3] ensures that list gets used for results 1, 2 and 3. Then "and day not in [11,12,13] excludes those specific numbers because they're exceptions to the rule that use "th" instead. Everything else also just uses "th". Hope that all makes sense.. Functionally, this was just the shortest version, I've also used several variations of that function, depending on whether I want to input an int or a str, or whether I want the output string to include the number first, or not. heh Here's a slightly longer version, more formally written, that takes a string and outputs a string with the number and suffix already together. Works well with time.strftime("%e"): def ordinalday(day: str) -> str: return day+['','st','nd','rd'][int(day)%10] if int(day)%10 in [1,2,3] and day not in ['11','12','13'] else day+'th' And of course these don't have to be used with days, that's just the most likely use, they can also works with other numbers, like 42nd. ;)
@jatindua58662 жыл бұрын
@@NikoKun Thank you for your time and such a clear explanation. Have a great day ahead!
@Eknoma2 жыл бұрын
This is why oneliners are bad, it would have been much much cleaner code if you just allowed more vertical space, for example: ```python def ordsuf(day): if 0 < day%10 3 or day in [11, 12, 13]: return "th" return ("th", "st", "nd", "rd")[day%10] ```
@happyjohn16562 жыл бұрын
@@Eknoma Or just import datetime & co. 😎 2:16 AM 11/22/2022
@demitri_t2 жыл бұрын
0:42 Important to know: the list comprehension is also MUCH faster faster than iteration approach.
@stuartberg80302 жыл бұрын
I consider myself very proficient in Python, but it had never occurred to me to use #4: print(*data). I will be using that very frequently from now on.
@jaksiz9 ай бұрын
a
@bettercalldelta2 жыл бұрын
1:57 If I remember correctly, you can also provide an argument to the print() function called 'sep', this will be the string that separates the elements (it's a space by default) So, for example: print(*data, sep='; ') Will print 0; 1; 2; 3; 4; 5
@jaylooppworld381 Жыл бұрын
Instead of sep I'll use end =';'
@sobbski2672 Жыл бұрын
@@jaylooppworld381that would add a ";" after your last element too. While sep only adds the separation between elements
@dewaard33012 жыл бұрын
Not a specific oneliner, but the fact that despite its reliance on indentation you can turn any python script into a oneliner is very helpful when sharing code snippets for commandline execution.
@sharangmorye7753 Жыл бұрын
func=lambda x : x+1 One liner for a function
@SmashPortal2 жыл бұрын
return a or b Will return b if a is falsy, else a (this helps if you want a default value b in case a == None or something similar).
@Soul-Burn2 жыл бұрын
For #6 Another alternative is to use reversed(x), which makes an iterator rather that a list, so it's useful when iterating it. For #8 I'd recommend using a list comprehension instead my_list = [int(x) for x in user_input.split()] , as it's more readable. For #9 It's a bad practice to use open on a single line rather than using with open(x). Also, strip will remove starting and ending whitespace which is not what you always want.
@demitri_t2 жыл бұрын
It's all true. A small note for #8. Indeed, a PEP recommends the list comprehension over the map call. But the map call is less verbose and more functional oriented ;)
@kidsfree66152 жыл бұрын
WARNING: ⚠⚠⚠ This video has BAD ADVICE To read a file please use a "with" statement as such: with open(filename,"r") as file: arr = [line.strip() for line in file] "with" statements will automatically close the file if there is an exception or when the "with" block is done. Otherwise the file may not be closed right away and can cause weirdness.
@demitri_t2 жыл бұрын
Indeed. But it's still a good one-liner if it's used through a command line :)
@gigachad88102 жыл бұрын
@@demitri_t wdym command line?
@demitri_t2 жыл бұрын
@@gigachad8810 python3 -c 'print(one-liner)'
@gigachad88102 жыл бұрын
@@demitri_t bro why would you use python to open files in a cli. just use cat or echo with a pipe. also, that doesnt fix the issue with that one liner outside of clis
@demitri_t2 жыл бұрын
@@gigachad8810 There are things difficult to do in bash. But the reason why I mentioned it is at 2:22 ;)
@DecimasoN2 жыл бұрын
You could also just use list comp for number 8 too [int(i) for i in a.split()]
@mienislav2 жыл бұрын
I think map is faster.
@DecimasoN2 жыл бұрын
@@mienislav only by a microscopically small amount, e.g. 1usec. This is reversed when it requires a lambda.
@Eknoma2 жыл бұрын
@@DecimasoN yeah, so it is (marginally) faster, AND more readable. That's a win-win
@darcash1738 Жыл бұрын
@@Eknoma I prefer the comprehension here bc you have to remember to use both map and then convert back to a list in the other one. The comprehension is easier to read
@dvdraymond2 жыл бұрын
Might fall into the realm of one-liners, but one tip I have is to remember that booleans are a sub class of integer, and thus can be used as the index of a list/tuple, etc. So for your #3 example, you could also write it as var = (99, 42)[3 > 2] I've used that for example when I'm writing a csv, and don't want to used the long "True" and "False" text representations. boolAsText = "NY"[boolValue] boolAsText = ("No", "Yes")[boolValue] etc. Maybe someone could come up with a better real world use of that.
@maccodifavole Жыл бұрын
I often use this when I have to return a specific value in the case the condition it's true or when the condition is false
@re.liable2 жыл бұрын
For 4: The `end` argument can be a ` ` to print the items in their own lines. I know the tip title says "without new lines" but I use both very often. There's also the `str.join` approach, e.g. `' '.join(data)` but that requires the items to be cast as strings first, if they're not already. Very handy if the joined string is to be used in another area however (i.e. not to be printed) I am really fond of that one-liner as it's the one that made unpacking click for me. I also use the "equivalent" of it in JS a lot (spread and rest)
@mayureshdharwadkar8532 жыл бұрын
If you want to ignore an exception, instead of try, except use supress exception
@michaelrogovin2 жыл бұрын
#9 - you need an additional line to close the file
@ansonmiu84642 жыл бұрын
Could use pathlib.Path - `pathlib.Path(filename).read_text().splitlines()`
@lokeshkalamalla2 жыл бұрын
Will 'with' work?
@dibbyo4562 жыл бұрын
@@lokeshkalamalla if you use use “with” you don’t need to close it, because it closes itself.
@forestcat5122 жыл бұрын
Thats what i immediately thought too
@jakobullmann75862 жыл бұрын
Not true IMHO. The file will be closed when the file object runs out of scope, which is at the end of the line.
@rgvn84062 жыл бұрын
Thanks for the video, I just wanted to add this :) # traditional function with def ``` def sum(a, b): return a + b ``` # lambda function ``` sum = lambda x, y: x + y ```
@lawrencedoliveiro91042 жыл бұрын
Or just use operator.add.
@Soul-Burn2 жыл бұрын
The function one is 99% of the times more readable than using a lambda. Only use a lambda when it's inline when e.g. calling a function. For example sorted(a, key=lambda x: x[0]) .
@Michael00000001 Жыл бұрын
the list(map(int, ...)) is fine but I prefer [int(x) for x in ] for readability.
@manojm90842 жыл бұрын
Waking up in the morning seeing this as the first video with so much useful information. How can a day be more better than this . Thank you 😊
@patloeber2 жыл бұрын
Glad you enjoyed it!
@Gruuvin12 жыл бұрын
Morning sex?
@RyanClark-gr9yb Жыл бұрын
@@patloeber You forgot that you can simultaneously step through two iterables in a single for loop: for (name,adress) in zip(names, adresses): print(name, address)
@palmerimsoaresdesa43185 ай бұрын
@@RyanClark-gr9yb The correct way for a video about One Liners would be: print([f"{name}, {address}" for name, address in zip(names, addresses)])
@glennmglazer2 жыл бұрын
I would include dict comprehension right after list comprehension.
@traal2 жыл бұрын
4:08 I would suggest pathlib for reading and writing files these days. from pathlib import Path; names = Path(“names.txt”).read_text().split()
@moahmadi222 жыл бұрын
Why is this better than with open?
@Sonyim4142 жыл бұрын
@@moahmadi22 read_text closes your file
@demitri_t2 жыл бұрын
4:06 The "r" mode is default, so ', "r"' can be omitted :)
@SkyyySi Жыл бұрын
You should be careful when using that reversing trick, because it creates a copy of your list (at least for the standard List; I think numpy arrays don't do that). You generally want to use `reversed()` instead, which won't copy. Also: NEVER use a bare `open()`. Only use it in a with statement.
@CatJuggernaut2 жыл бұрын
A lot of people have pointed out that in 8, you could use a list comp even though map is shorter, more clear, and faster. The real issue it that you gave no safe catch for if the data could not be converted to integers.
@demitri_t2 жыл бұрын
I doubt the map is faster. Is it really so? The interpreter should convert a comprehension into a single C call as well as it does with a map call.
@jprak1329 Жыл бұрын
#8. For better clarity, we can use list comprehensions like this a = '1 3 5 6' b = a.split() c = [int(i) for i in b] print(c)
@jprak1329 Жыл бұрын
Memory efficiency Using gerator objects a = '1 3 5 6' b = a.split() c = list(int(i) for i in b) print(c)
@UnknownGamer-lw7zp2 ай бұрын
a = "1 3 5 6" print(list(map(int,a.split())))
@kpbendeguz2 жыл бұрын
checking zero on None value with 'or' if not var: var = 'something' you can use: var = var or 'something' usefull when you expect a certain type and wanna rule out None: (d or {}).get('element') (L or [None])[0]
@matthewrobertson88242 жыл бұрын
The multiple variable assignments ie (a, b = b, a) blew my minds a few weeks ago coming from other languages so handy
@5ucur2 жыл бұрын
In list comprehension, you can even use else, but you have to put the if-else before the for, like so: a = [n if n % 2 else -n for n in some_list] This will result in a list like [1, -2, 3, -4, 5], from some_list as [1, 2, 3, 4, 5]. And you can do comprehension with other types like dicts too!
@vorpal222 жыл бұрын
The dict setdefault method is one that has come in handy for me more times than I can count.
@zapp77462 жыл бұрын
gr8 video : btw you can use if statments without using them : print(["hello","world"][1>2])
@pfizerpflanze Жыл бұрын
#2 is also range(0,10,2), instead of the if statement
@tamiltrending24242 жыл бұрын
Please do more videos like this. Kind of refresher
@studyingasyouwere2 жыл бұрын
Always an insightful video. These types of videos consistently inspire me to post coding content myself! Thank you :)
@patloeber2 жыл бұрын
Go for it!
@traal2 жыл бұрын
3:47 this should have been a list comprehension: my_list = [int(x) for x in user_input.split()]
@Eknoma2 жыл бұрын
Using map is much more readable, and almost always faster
@demitri_t2 жыл бұрын
@@Eknoma I doubt it's faster. The comprehension should basically be interpreted into a map call (in the lower C level). Otherwise PEP wouldn't recommend comprehensions over map calls.
@Eknoma2 жыл бұрын
@@demitri_t It literally takes 2 seconds to check for yourself... why write a comment disregarding a result without even checking? On my system, list(map(int, s.split())) takes roughly 18% less time than [int(i) for i in s.split()] There would be literally no point in map if it was slower than a normal for loop... so obviously it has to be faster at some things
@demitri_t2 жыл бұрын
@@Eknoma Yep, ~20% is expected for int(). But this is just because you tested the simplest case. Try e.g. lambda i: i * i instead. And I didn't tell anything about a normal loop. Did you test it as well? P.S. Indeed I didn't profile anything myself, I just found results in the stackoverflow :)
@Eknoma2 жыл бұрын
@@demitri_t What are you talking about? Of course using a lambda adds performance overhead... So you first say you doubt using map for it's intended purpose is fast, and then you later say using it in a bad way is slow, what arr you getting at?
@norb36952 жыл бұрын
Amazing video man, cheers!
@patloeber2 жыл бұрын
Thank you! Cheers!
@anamoyeee9 ай бұрын
"One liners" "Let's use the semicolon to make it technically a one liner"
@dvdraymond2 жыл бұрын
I know the point was the one-liner part of it, but opening a file in text mode without explicitly specifying the encoding just makes me shiver. You should never just assume the encoding will be the same as your system default, and if you're the one making the file you should always be able to know exactly what encoding your file is going to be in. Plus having the same script make different files when run on different systems is bad.
@rezakghazi Жыл бұрын
Which theme are you using for your vscode?
@vladepast4936 Жыл бұрын
Hi how to write to a file with oneliners? Thank you!
@gamefacierglitches2 жыл бұрын
There are 2 types of people that clicked this video... I am both
@nagitoyup69292 жыл бұрын
dict2|=dict1 to merge two dictionaries in one line(3.9+)
@lordadamant81822 жыл бұрын
Unironically a fantastic resource to have.
@minhazulislam46822 жыл бұрын
He Pat, here after a long time. Just wanna let you know that I love your videos. Keep on making the good stuff.
@mayorc Жыл бұрын
Doest that 9th one liner requires to manually close the opened file? Cause with "with" you wouldn't need that. So does the list comprehension bypass the closing or not?
@hemanth81952 жыл бұрын
We can also use eval fn for str list 🙌🏾
@b213videoz2 жыл бұрын
eval is EVIL
@pknepps2 жыл бұрын
is it possible to use print(*data) to print each value on a new line?
@MigzPigz2 жыл бұрын
One way to do that is print(*data, sep=' '). After it unpacks the data, the items essentially become different params in the print() call and then you use sep=' ' to insert a new line instead of the default space between each item.
@shamrock19612 жыл бұрын
What version of python were you using here? 3.10 or 3.1?
@patloeber2 жыл бұрын
3.11
@olivierbegassat851 Жыл бұрын
2:07 "add a semicolon to stay in the same line" that's one way to make a one liner 😂
@ghaythghannouchi34272 жыл бұрын
You forgot the conditional assignment it s a great technique to use
@AbcdcDym2 жыл бұрын
Tmatrix = [list(i) for i in zip(*matrix)]
@gamesandstuff77242 жыл бұрын
Importing doesn't count. By that logic, I could make my own module with any function I want, and say that it is 1 line. Also, I could separate my entire program with semicolons and say it is one line, so that definitely doesn't count.
@schogaia2 жыл бұрын
does 9. have an implicit context manager?
@MaxMustermann-on2gd2 жыл бұрын
I was wondering as welll ..
@lawrencedoliveiro91042 жыл бұрын
Remember that CPython does reference counting, so objects are automatically disposed when their refcount goes to zero. For file objects, this means the file is automatically closed. I wouldn’t recommend relying on that for files open for writing, since then you might miss I/O errors because the volume is full etc. For files open readonly, I do this sort of thing all the time.
@schogaia2 жыл бұрын
@@lawrencedoliveiro9104 thank you
@patloeber2 жыл бұрын
Good question! Yes I agree with Lawrence. Python docs say "Do not depend on immediate finalization of objects when they become unreachable (so you should always close files explicitly)." So my one-liner is not best practice, but probably also doesn't do harm in this case... See docs: docs.python.org/3/reference/datamodel.html#index-2
@MaxMustermann-on2gd2 жыл бұрын
@@patloeber thank you and @Lawrence ... Yes, i'd also argue that it isn't best practice, but interesting to know that cpython takes care of this, so from a technical perspective it is indeed "clean" code.
@isaacnaughton52062 жыл бұрын
Great video: A nice one-liner for CSV to JSON: python -c 'import csv, json, sys; print(json.dumps([dict(r) for r in csv.DictReader(sys.stdin)]))'
@_Garm_2 жыл бұрын
you forgot the.. "subscribe" one liner :P
@fgamboa2 жыл бұрын
Thanks so much for sharing! Greetings from Mexico!
@estelisarva38542 жыл бұрын
Thank you, I love you bc I learn good tricks from you bro. Waves from Bolivia.
@_vishal_01 Жыл бұрын
Intresting! Thanks
@RahnAbbott8 ай бұрын
For #2 why wouldn't you just use ... print([i*i for i in range(10) if i %2 ==0]) and then it truly is a one liner. Not declaring a variable and then printing the variable?
@castlecodersltd2 жыл бұрын
Great tips, thanks ☺
@ProfRoxas2 жыл бұрын
I usually like one liners, but sometimes i take it too far... like when i made a 200+ letter long one liner... since then i think again if it's worth
@mienislav2 жыл бұрын
5th is not exactly a oneliner. There are two instructions of code. If we treat this as a one-liner, then we can wrap all Python codes in just one line adding everywhere semicolons.
@etdr2 жыл бұрын
Good list. My only gripe is that ternaries are expressions, not statements!
@elhombreloco36802 жыл бұрын
But assigning the ternary to a variable does make it a statement
@etdr2 жыл бұрын
@@elhombreloco3680 True, but the ternary itself is still an expression, that's *why* you can assign its value to a variable
@omega_no_commentary Жыл бұрын
I always use this trick to print iterables, item by item in a single line: _ = [print(a) for a in iterable]
@ryankhart Жыл бұрын
I guess I'm an advanced Python developer because I've used all of those before. I consider myself to be a beginner to Python, so maybe I'm selling myself too short and should start applying for jobs.
@farazahmed16682 жыл бұрын
amazing work thank you so much.
@_Elvyra._2 жыл бұрын
You just commited a crime by using semicolons in python
@kychemclass58502 жыл бұрын
Great tips! Tqqqqqq
@RedditTaskForce2 жыл бұрын
can i use these one liners on a date
@michaelmitchell1552 жыл бұрын
Very cool video. I've been using python, and am always looking to make life easier. Thanks!
@estelisarva38542 жыл бұрын
Hi, do you have videos with regex module?
@lawrencedoliveiro91042 жыл бұрын
2:13 Don’t you mean, the first day of the next year? So that on 31st December, it will return 1 day left, not 0 days left.
@patloeber2 жыл бұрын
nice catch, yeah I should probably not exclude New Year's Eve
@Allen-by6ci2 жыл бұрын
Really good video.. thanks!
@pythonwala5102 жыл бұрын
What is the theme name you are using?
@soshians32842 жыл бұрын
palenight
@DefenceJet2 жыл бұрын
Pls anybody ans why if i write this code will return false A = 20 A = int(A) Print(a is int)
@bilaldz93042 жыл бұрын
you are comparing value to a class, it will only return true in this case: print(type(a) is int) this is what you need to check if value is int: print(instance(a, int))
@DefenceJet2 жыл бұрын
@@bilaldz9304 Thanks sir
@lidarman22 жыл бұрын
Is it all in the... timing?
@jorgehenriquesoares78802 жыл бұрын
#5 is actually cheating since you can write the whole core in one line using semicolon instead of a line break. But this video is full of good tips, thank you..
@lukakorencan55002 жыл бұрын
hi, does anyone know which extension for vscode he uses so his output updates as he types?😊
@jaylooppworld381 Жыл бұрын
Don't I dont know but you can us import os; os.system('cls') Put this code in the top level of you code and each time you run the code, the terminal will delete the Last output before the new output is shown in the terminal
@iamfkhn2 жыл бұрын
Helpful 🙏
@patloeber2 жыл бұрын
Glad you think so!
@robertjulesyoung99942 жыл бұрын
cool! thanks
@mattzoozb13852 жыл бұрын
A few of these remind me of excel formulae
@lawrencetaulk7898 Жыл бұрын
wonderful gift.
@Nick-lc3ll2 жыл бұрын
so in 2 you show how to use list comps but in 8 you miss out on the most obvious use case of them? a list comp would look much nicer than a map here imo
@prashlovessamosa2 жыл бұрын
Thank you
@patloeber2 жыл бұрын
You're welcome
@avrahamwolosh50012 жыл бұрын
Reading a file in one line isn't great practice. you do need to close the file when you are done
@YamiSuzume2 жыл бұрын
very fast paced. Wouldn't hurt to give the people a decent amount of time to read without rewinding the video. And since 1 and 7 are the same, its kinda cheated :D Otherwise, nice vid
@shubhamthedeveloper Жыл бұрын
This man is just 😎 😎 !
@KTiwari72 жыл бұрын
excellent!
@patloeber2 жыл бұрын
Thanks!
@whonayem012 жыл бұрын
Thanks
@DrOsbert2 жыл бұрын
This is a real deal!
@ibexy2 жыл бұрын
Now try to do these in Java or C# 😉
@harrydparkes Жыл бұрын
Using a semi colon in number five is both cheating and disgusting. Assuming datetime was already imported on a different line however, it is fine
@jcatlantis2 жыл бұрын
You are the best ;)
@AliMughrabi2 жыл бұрын
I know them all but anyway I enjoy when I watching it 😂😂 Thanks ♥♥
@sillybuttons9252 жыл бұрын
ternary == danger
@letsjoinhands2 жыл бұрын
You're really good but a bit fast. Your presentation always moves quite fast. If you could adjust the speed a but that would allow me to follow you more easily.
@ssigitas69 Жыл бұрын
Nice. I'm beginner and I didn't know any of them. Thanks. But what I don't like in your videos 📸....you are too fast for me 😂 I need to watch your videos many times to catch it 😉