python get second item in list

My sink is not clogged but water does not drain. Another solution with map (with slightly different syntax than other answers). Then it iterates through the list, checking to see if any values are lower than the lowest so far, or the second lowest so far. Also, this is the most simplest and most used solution to get the last element of list. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing, Do you want the second smallest value, or do you want the smallest value greater than 0? My data consist of Latitude in object type : Then, I split after the decimal point using this code: which is good but not quite there yet. You have a dictionary in a list. How to Get the Last Element of a Python List? python access second element of list - Stack Overflow You can use a loop to find the lowest and second lowest value in one pass. Asking for help, clarification, or responding to other answers. Iterating over 2 elements in a list but repeating the second element in the next iteration. Most pythonic way of getting index of the last list item. Help on built-in function zip in module builtin: zip(seq1 [, seq2 []]) -> [(seq1[0], seq2[0] ), ()]. New! Let's discuss some other ways, Has these Umbrian words been really found written in Umbrian epichoric alphabet? Find centralized, trusted content and collaborate around the technologies you use most. OverflowAI: Where Community & AI Come Together, Find the index of the second occurrence of a string inside a list, Behind the scenes with the folks building OverflowAI (Ep. The problem with this solution is that in case of. prosecutor. Note: In Python3, zip returns an iterator, so instead use list(zip(*elements)) to return a list of tuples. How to find index of second occurrence of a phrase in a string in Python 3? New! Instead, you want to add the zip into a list to extract the elements you want based on the index. Thanks for contributing an answer to Stack Overflow! Not the answer you're looking for? How Do You Get Every Other Element From a Python List? - Codefather How can I make it so I can iterate through every 2 items? A student of Python will also learn that lists are ordered, meaning that the order of their elements is fixed. Join two objects with perfect edge-flow at any stage of modelling? Ok, but what about common in almost every language way items[len(items) - 1]? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing. If I allow permissions to an application using UAC in Windows, can it hack my personal files or data? python - Accessing the second element of a list for every row in pandas The British equivalent of "X objects in a trenchcoat". I'm making a basic website and using MySQL to get stored password data. Python | Accessing nth element from tuples in list To learn more, see our tips on writing great answers. Does Python have a ternary conditional operator? Unpacking "If they have a question for the lawyers, they've got to go outside and the grand jurors can ask questions." i just gav simple example!! NOTE: it's worth knowing that this would also remove the last element from the list. python - Best way to get second item of each list inside of a 2D list The canonical way is a list comprehension: I would suggest to use index 1 instead of -1, since the question is asking for "the second item" and not for the last one, even thought the sublists are of lenght 2. zip() with * can be used to unzip a list. If I allow permissions to an application using UAC in Windows, can it hack my personal files or data? List of lists middle element extraction in python, Best way to get the nth element of each tuple from a list of tuples in Python. Usually, mutating the original list is not recommended. To learn more, see our tips on writing great answers. print(list(l2)) gives TypeError: 'NoneType' object is not callable, Your answer could be improved with additional supporting information. To reiterate what I want: Downvoted because I feel the core of this answer is incorrect. What Is Behind The Puzzling Timing of the U.S. House Vacancy Election In Utah? Now how do I get the actual password out of this list [{'password': '71cf12724462a57af2effd96223f13e3cc2d11eb0259bada9abf6a5a5a50c85892cbad9b8e00a01f1b1f4c2cebfb665c34691eb320e3a61b6e22081373cbd424'}] and into a string? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing. I was wondering if there was a more elegant way of doing this. from former US Fed. @dee Try to google that error message, or look at the Pandas docs. (with no additional restrictions). Connect and share knowledge within a single location that is structured and easy to search. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing. How do I keep a party together when they have conflicting goals? To have the second element (the element with index 1) of each sublist, I would suggest a list comprehension: new_list = [sublist [1] for sublist in items] If you want the last element (the element with index -1) of each sublist, you just have to change the index: new_list = [sublist [-1] for sublist in items] Why would a highly advanced society still engage in extensive agriculture? No longer works, probably this got lost in the transition form Python 2 to 3: "TypeError: 'zip' object is not subscriptable." You want to keep the value after the decimal as an intenger? Sci fi story where a woman demonstrating a knife with a safety feature cuts herself when the safety is turned off. Returns: A zero based index of first occurrence of given element in the list or range. Which generations of PowerPC did Windows NT 4 run on? Asking for help, clarification, or responding to other answers. Why would a highly advanced society still engage in extensive agriculture? Lastly, output the actual latitude. Is there any easy option to keep the double values? Connect and share knowledge within a single location that is structured and easy to search. method2 = 'list(map(itemgetter(1), elements))' renders the old behavior. But unfortunately i forgot that dict cannot have double values so instead of getting 965, 988 as the answer i receive only 965. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. How can I change elements in a matrix to a combination of other elements? I have something like: elements = [ (1,1,1), (2,3,7), (3,5,10)] I wish to extract only the second elements of each tuple into a list: seconds = [1, 3, 5] I know that it could be done with a for loop but I wanted to know if there's another way since I have thousands of tuples. Schopenhauer and the 'ability to make decisions' as a metric for free will, The British equivalent of "X objects in a trenchcoat". vara= ["10","11","12","13","14","15"] print ( [vara [i] for i in (1,2,5)]) Output: ['11', '12', '15'] Method 2: Storing list and index positions into two different variables and then running the loop to search for those index positions. @MichaelWu There is no sense to do that. A slice of a list returns a new list - so we can slice from -1 to the end if we are going to want the element in a new list: This has the upside of not failing if the list is empty: Whereas attempting to access by index raises an IndexError which would need to be handled: But again, slicing for this purpose should only be done if you need: As a feature of Python, there is no inner scoping in a for loop. WW1 soldier in WW2 : how would he get caught? Can you have ChatGPT 4 "explain" how it generated an answer? Making statements based on opinion; back them up with references or personal experience. Is it unusual for a host country to inform a foreign politician about sensitive topics to be avoid in their speech? To find the length, use the len () function: print(len(programming_languages)) #output is 6. This is semantically the last thing that the name, item, was bound to. [duplicate], Iterating over every two elements in a list [duplicate], Behind the scenes with the folks building OverflowAI (Ep. Also, added numpy array method, which is simpler to read (but arguably simpler than the list comprehension). if you are embarassed that results are tuples we can turn them into lists simply using map built-in: Lots of pure Python approaches here. 594), Stack Overflow at WeAreDevelopers World Congress in Berlin, Temporary policy: Generative AI (e.g., ChatGPT) is banned, Preview of Search and Question-Asking Powered by GenAI. Method-6: Replace items in a Python list using map () Function. I have tried converting it to an array, string and dict to no avail. Not the answer you're looking for? Which generations of PowerPC did Windows NT 4 run on? find_nminimum(lis,0) gives minimum of the list. Those would be: 965, 988. To learn more, see our tips on writing great answers. The value of 0.0 was originally a negative value (its a noisy data point) and so I used: I cannot remove the value entirely using a=a[a>0.0] as it is important that I keep all of the data points (these are y values that have corresponding x values). So some_list[-1] gets the last element, some_list[-2] gets the second to last, etc, all the way down to some_list[-len(some_list)], which gives you the first element.. You can also set list elements in this way. Not the answer you're looking for? What is the latent heat of melting for a everyday soda lime glass. Method 1: Using List Comprehension Method 2: Using map () and itemgetter () Method 3: Using zip () function Summary Method 1: Using List Comprehension Iterate our all the tuples in the list using a List Comprehension, and select second element of each tuple during iteration. WW1 soldier in WW2 : how would he get caught? For example, Consider a list of US national parks. How to Use the index () Method The index () method gives us a straightforward way to get the index of an item. That's because it will return an iterator. Pythonic way often is not self-explanatory, need more attention where you have to introduce new persons to project and, of course, wouldn't work when you have to switch to other languages like Java - you can't use Python specific knowledge. is there a limit of speed cops can go on a high speed pursuit? Your example is how I would accomplish this. How can I change elements in a matrix to a combination of other elements? Yes, if we don't need to access the index, that might be a better way. Users find it difficult to understand code only answers with no explanation. so that advantage doesnt matter. Connect and share knowledge within a single location that is structured and easy to search. 1. i have following list: parent_child_list with id-tuples: Example: i would like to print those values which are combined with the id 960. For sorting a list of tuples by 2nd item or ith item, we need to pass our custom comparator i.e. The zip function does not return a list, but a "zip" object now. How do I split a list into equally-sized chunks? Not the answer you're looking for? How to select all items for a particular dimension in a list? Thanks for contributing an answer to Stack Overflow! It starts by setting lowest to the lower of the first to elements, and secondLowest to the other element. How do I get the number of elements in a list (length of a list) in Python? rev2023.7.27.43548. Which generations of PowerPC did Windows NT 4 run on? Did active frontiersmen really eat 20,000 calories a day? key function in the sort (), Copy to clipboard you have a nested list that you can access this way: To have the second element (the element with index 1) of each sublist, I would suggest a list comprehension: If you want the last element (the element with index -1) of each sublist, you just have to change the index: For the list you shown the two lines will give the same list, but when the sublists have more than two elements the two solution will give different results. @Oleg I don't understand in the 'dict` method how the code understands that we want to look at the second element. Initialize a dictionary test_dict with key-value pairs. I have modified an example from the documentation to indicate which item in a sequence each index references, in this case, in the string "Python", -1 references the last element, the character, 'n': This method may unnecessarily materialize a second list for the purposes of just getting the last element, but for the sake of completeness (and since it supports any iterable - not just lists): The variable name, head is bound to the unnecessary newly created list: If you intend to do nothing with that list, this would be more apropos: Or, really, if you know it's a list (or at least accepts subscript notation): I wish Python had a function for first() and last() like Lisp does it would get rid of a lot of unnecessary lambda functions. Find centralized, trusted content and collaborate around the technologies you use most. In fact, you can do much more with this syntax. Why is an arrow pointing through a glass of water only flipped vertically but not horizontally? New! Is it unusual for a host country to inform a foreign politician about sensitive topics to be avoid in their speech? Iterating through twos list of lists in python, Iterate ONLY first and second list python, Iterate and select every two elements of a list python. Would fixed-wing aircraft still exist if helicopters had been invented (and flown) before them? I think string is suitable because then I need to use match these value with user input. What is the least number of concerts needed to be scheduled in order that each musician may listen, as part of the audience, to every other musician? Python | Get last element of each sublist - GeeksforGeeks You can also use the length to get the last element: If the list is empty, you'll get an IndexError exception, but you also get that with arr[-1]. Can you have ChatGPT 4 "explain" how it generated an answer? But given that your goal is to plot the separated values, I think there's a case to be made here for the simplicity of Pandas - just drop the list as-is into a data frame and plot(): Thanks for contributing an answer to Stack Overflow! For What Kinds Of Problems is Quantile Regression Useful? How can I find a first occurrence of a string from a list in another string in python. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. OverflowAI: Where Community & AI Come Together, Behind the scenes with the folks building OverflowAI (Ep. @Pneumokok You make point, but I would argue that list indexing is a, Although it's not very pythonic I think this is in some respects better than the. Find centralized, trusted content and collaborate around the technologies you use most. How and why does electrometer measures the potential differences? Though I am not sure if integer will work better .. Hmm, whats the use for this? This is a simple method where you can do the same operation on. Not the answer you're looking for? Where the distinction being made is that returning an empty list object or empty str object is more "last element"-like then an exception object. How can I find the second occurrence of a string inside a list? Method 1: Directly using a loop to search for specified indexes. New! Find the index of an item in a list in Python | note.nkmk.me is there a limit of speed cops can go on a high speed pursuit? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. send a video file once and multiple users stream it? Connect and share knowledge within a single location that is structured and easy to search. Find centralized, trusted content and collaborate around the technologies you use most. Making statements based on opinion; back them up with references or personal experience. For example: Here a try with zip, zip() will makes iterator that aggregates elements based on the iterables passed, and returns an iterator of tuples, so map() function is used to make the tuples to list : One-liner using zip built-in and unpacking. Say, at least 5 initial number from input matches these value and output the result. find_nminimum(lis,n) gives the nth minimum in the list. So lets consider that we have a list a = [1,2,3,4], in Python List can be manipulated to give us part of it or a element of it, using the following command one can easily get the last element. What is Mathematica's equivalent to Maple's collect with distributed option? Are arguments that Reason is circular themselves circular and/or self refuting? Say, one needs to do the same for the 3 or 10th elements. Find centralized, trusted content and collaborate around the technologies you use most. I would like to get a new list containing the last element of each nested list: But this feels very clumsy for such a simple thing. Thus you may want some exception handling around your inner loop. Iterating the whole list and getting, the second last element. How does this compare to other highly-active people in recorded history? Making statements based on opinion; back them up with references or personal experience. some_list[-1] is the shortest and most Pythonic. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Does Python have a ternary conditional operator? you do intend to remove the last element from the list, treating it like a stack. (happy to upvote if I missed something). main.py Can YouTube (e.g.) Single Predicate Check Constraint Gives Constant Scan but Two Predicate Constraint does not. Are modern compilers passing parameters in registers instead of on the stack? tuples, sets, or dictionaries ). One certainty is that exceptions halt your app. Find the index of the second occurrence of a string inside a list Ask Question Asked 9 years, 11 months ago Modified 9 years, 11 months ago Viewed 17k times 4 This is my list and code: x= [ ["hi hello"], ["this is other"], ["this"], ["something"], ["this"], ["last element"]] for line in x: y=x.index (line) #code Connect and share knowledge within a single location that is structured and easy to search. Can YouTube (e.g.) Is it normal for relative humidity to increase when the attic fan turns on? Below is an example of a Python function which gets the second smallest value in a list of numbers. For What Kinds Of Problems is Quantile Regression Useful? If you change your algorithm in one place, it may have an unintended impact on another line of code. I don't know why you'd do it, but for completeness, since reversed returns an iterator (which supports the iterator protocol) you can pass its result to next: But I can't think of a good reason to do this, unless you'll need the rest of the reverse iterator later, which would probably look more like this: To prevent IndexError: list index out of range, use this syntax: lst[-1] is the best approach, but with general iterables, consider more_itertools.last: list[-1] will retrieve the last element of the list without changing the list.

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