To subscribe to this RSS feed, copy and paste this URL into your RSS reader. What is Mathematica's equivalent to Maple's collect with distributed option? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. 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 You can also set list elements in this way. Return a list of tuples, where each tuple contains the i-th element Example: You have the list ['Alice', 'Bob', 'Liz'] and you want to get the last element 'Liz'. first element in the list has index 0 and second element in index is 1. send a video file once and multiple users stream it? In response to "How do I turn the list into a string": It is returning a dictionary inside of a list, so call the first index of the list to return just the dictionary, then use 'password' as the key for the dictionary to return the password. In response to "How do I turn the list into a string": It is returning a dictionary inside of a list, so call the first index of the list to return just the dictionary, then use 'password' as the key for the dictionary to return the password. you know the list has elements in it, or are prepared to handle the exception if it is empty, and. To learn more, see our tips on writing great answers. @dee Try to google that error message, or look at the Pandas docs. What Is Behind The Puzzling Timing of the U.S. House Vacancy Election In Utah? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. This is probably obvious but I would mention. How do I clone a list so that it doesn't change unexpectedly after assignment? In fact, you can do much more with this syntax. How does this compare to other highly-active people in recorded history? To learn more, see our tips on writing great answers. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing. Which generations of PowerPC did Windows NT 4 run on? python - Best way to get second item of each list inside of a 2D list python - Iterate every 2 elements from list at a time - Stack Overflow Negative Indexing Negative indexing means start from the end Problem: Given a list. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Though I am not sure if integer will work better .. Hmm, whats the use for this? Does Python have a ternary conditional operator? Let's discuss some other ways, What Is Behind The Puzzling Timing of the U.S. House Vacancy Election In Utah? Thanks for contributing an answer to Stack Overflow! Is it superfluous to place a snubber in parallel with a diode by default? Get first few elements of tuples from list of list of tuples, How to extract the n-th elements equal to a value from a list of tuples in python, Get all first element of tuples from list of lists of tuples in Python, How to get particular element from list of tuples, Python extract elements from list of tuple, Sci fi story where a woman demonstrating a knife with a safety feature cuts herself when the safety is turned off. Why would you "avoid" an IndexError? rev2023.7.27.43548. If you're performing a complete iteration over the list already, the last element will still be referenced by the variable name assigned in the loop: This is not semantically the last thing in the list. Since lists can have duplicate items, there may be multiple occurrences of the item we are looking for. How do I split a list into equally-sized chunks? i just gav simple example!! To reiterate what I want: is there a limit of speed cops can go on a high speed pursuit? Method #1 : Using list comprehension List comprehension is the simplest way in which this problem can be solved. How and why does electrometer measures the potential differences? OverflowAI: Where Community & AI Come Together, Iterate every 2 elements from list at a time, Behind the scenes with the folks building OverflowAI (Ep. My sink is not clogged but water does not drain. How and why does electrometer measures the potential differences? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Why do code answers tend to be given in Python when no language is specified in the prompt? Why is "1000000000000000 in range(1000000000000001)" so fast in Python 3? Add a comment. Find centralized, trusted content and collaborate around the technologies you use most. Algebraically why must a single square root be done on all terms rather than individually? However, pop method will remove the last element from the list. send a video file once and multiple users stream it? How to iterate over rows in a DataFrame in Pandas. How to Make a List in Python - Declare Lists in Python Example How to select all items for a particular dimension in a list? Do the 2.5th and 97.5th percentile of the theoretical sampling distribution of a statistic always contain the true population parameter? Users find it difficult to understand code only answers with no explanation. How to get the last element in the Python list How do I get the number of elements in a list (length of a list) in Python? New! There is another way. Access the last element with pop() method. How to get index of the last item with a given value, How to get the last item of a list in python. is there a limit of speed cops can go on a high speed pursuit? Join two objects with perfect edge-flow at any stage of modelling? Then, match the value after decimal with value after decimal point from user. How to access the last element of this list? Is the DC-6 Supercharged? The some_list[-n] syntax gets the nth-to-last element. Iterating the whole list and getting, the second last element. Python | How to get the last element of list - GeeksforGeeks Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing. Why do we allow discontinuous conduction mode (DCM)? The British equivalent of "X objects in a trenchcoat". Asking for help, clarification, or responding to other answers. Are arguments that Reason is circular themselves circular and/or self refuting? Were all of the "good" terminators played by Arnold Schwarzenegger completely separate machines? Usually, mutating the original list is not recommended. Thus this should only be used to get the last element if you. The simplest way to display last element in python is. And then the value for key "password" from the dictionary. main.py Making statements based on opinion; back them up with references or personal experience. How can Phones such as Oppo be vulnerable to Privilege escalation exploits. Does anyone with w(write) permission also have the r(read) permission? Did active frontiersmen really eat 20,000 calories a day? A student of Python will also learn that lists are ordered, meaning that the order of their elements is fixed. select specific elements of second dimention of a 2D array. Trying to get the first item in a list within a panda dataframe. Connect and share knowledge within a single location that is structured and easy to search. Are self-signed SSL certificates still allowed in 2023 for an intranet server running IIS? how to make it list of lists instead of list of tuples? I'm trying to obtain the n-th elements from a list of tuples. its complicated! Can you have ChatGPT 4 "explain" how it generated an answer? How do I create a directory, and any missing parent directories? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing. Making statements based on opinion; back them up with references or personal experience. Are modern compilers passing parameters in registers instead of on the stack? For example, user input '1.23456' (5 decimal place-OK) but in my dataframe, I have '1.2345678'. Why is {ni} used instead of {wo} in ~{ni}[]{ataru}? If I allow permissions to an application using UAC in Windows, can it hack my personal files or data? As can be seen in a[1] there is a negative value in the array. For, The smallest value, which may include 0.0. If you want to iterate pairwise every 2 items, you can do this: for item1, item2 in zip (items [::2], items [1::2]): print (item1, item2) Yes, if we don't need to access the index, that might be a better way. How can I make it so I can iterate through every 2 items? Find centralized, trusted content and collaborate around the technologies you use most. To avoid "IndexError: list index out of range", you can use this piece of code. 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. 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. What does it mean in terms of energy if power is increasing with time? Python3 test_list = [1, 4, 5, 6, 3, 5] print("The original list is : " + str(test_list)) for i in range(0, len(test_list)): if i == (len(test_list)-1): Method 1: Directly using a loop to search for specified indexes. Why is the expansion ratio of the nozzle of the 2nd stage larger than the expansion ratio of the nozzle of the 1st stage of a rocket? I give me error: Did you try the code? How can I return the name of the states based on population from the list? rev2023.7.27.43548. The important thing, though, is that you use a number that you know will not be the lowest. Help on built-in function zip in module builtin: zip(seq1 [, seq2 []]) -> [(seq1[0], seq2[0] ), ()]. Thus you may want some exception handling around your inner loop. Manga where the MC is kicked out of party and uses electric magic on his head to forget things. Find centralized, trusted content and collaborate around the technologies you use most. The first time it gets "this", it works properly, but for the second time, it gets the index of the first "this" only! Can I use the door leading from Vatican museum to St. Peter's Basilica? Does anyone with w(write) permission also have the r(read) permission? To learn more, see our tips on writing great answers. 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. Do the 2.5th and 97.5th percentile of the theoretical sampling distribution of a statistic always contain the true population parameter? Examples: Input : [ [1, 2, 3], [4, 5], [6, 7, 8, 9]] Output : [3, 5, 9] Input : [ ['x', 'y', 'z'], ['m'], ['a', 'b'], ['u', 'v']] Output : ['z', 'm', 'b', 'v'] Approach #1 : List comprehension Python3 def Extract (lst): In the example below, we find the index of the first occurance and then find the index of the first occurance in the sub-list that begins just after the first occurance. Can YouTube (e.g.) How to get the last occurrence of list as output? I know this is an old question, just a different approach. This probably should be the default behaviour, it's much easier to work with: You can use pd.DataFrame.iterrows() to iterate by row and then select the proper index for your list. python - Accessing the second element of a list for every row in pandas Python Find in List - How to Find the Index of an Item or Element in a List Are arguments that Reason is circular themselves circular and/or self refuting? Let's get creative and come up with multiple ways to solve this problem! The best option I can find is operator.itemgetter(), which is implemented in native code and should perform fine with Series.apply(): Note Series.str.split() also accepts an expand=True argument, which returns a new DataFrame containing columns 0..n rather than a series of lists. Python Access List Items - W3Schools Connect and share knowledge within a single location that is structured and easy to search. I would recommend using numpy arrays. What is Mathematica's equivalent to Maple's collect with distributed option? Maybe a lambda function could do it better, but IMO it would be less clear. Yes, if we don't need to access the index, that might be a better way. 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? I used this with pandas duplicated like this : duplicated = df.duplicated(subset=["Full Name"],keep=False) data_read5 = next(iter(duplicated[::-1])). You can use a loop to find the lowest and second lowest value in one pass. Ok, but what about common in almost every language way items[len(items) - 1]? Single Predicate Check Constraint Gives Constant Scan but Two Predicate Constraint does not. Algebraically why must a single square root be done on all terms rather than individually? It depends on what you want to do with your list because the pop() method will delete the last element. By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. Can you have ChatGPT 4 "explain" how it generated an answer? How to find index of second occurrence of a phrase in a string in Python 3? @AMC This was the first idea that came to mind, what other solution do you have? Negative indexing means beginning from the end, -1 refers to the last item, -2 refers to the second-last item, etc. I don't understand how this answer to "how to get the last element?" l = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] l2=map(None,*[iter(l)]*2) print(l2) gives map object instead of k,v pairs. How does this compare to other highly-active people in recorded history? Are modern compilers passing parameters in registers instead of on the stack? Can Henzie blitz cards exiled with Atsushi? You can read more about list comprehension here and here. Why would a highly advanced society still engage in extensive agriculture? Find centralized, trusted content and collaborate around the technologies you use most. My sink is not clogged but water does not drain. "Sibi quisque nunc nominet eos quibus scit et vinum male credi et sermonem bene". Could the Lightning's overwing fuel tanks be safely jettisoned in flight? python If you want to handle that exception, use a try/except -- that's what it's there for. How to find the shortest path visiting all nodes in a connected graph as MILP? 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, python pandas: access the element of the list in DataFrame, Accessing every 1st element of Pandas DataFrame column containing lists, retrieve list element from pandas dataframe column, Accessing other than first element in list doesn't work, Getting the first element from each list in a column of lists, Trying to get the first item in a list within a panda dataframe, Access the first element of a sorted list, Returning the first item of row value in pandas dataframe. Accessing the last element from the list in Python: 1: Access the last element with negative indexing -1, 2.