Python merge two lists alternating

Share Tweet Facebook Facebook. Views: I know how to figure out this task in grasshopper but what I am trying here is to translate examples i could do in grasshopper to Python, so that i can learn how to script properly I am nor sure whether my solution is good for you to learn. But is only 3 lines of code. See the attached. It complicates things. Djordje's one is more appropriate for your progress. I'm new to python but i think that it could help me learn and understand that stuff, to actually translate grasshopper "bricks" to written PYTHON code Add the items of both list sequentially to the list of results.

As a side note: the way Python solves a specific problem may or may not differ hugely from the way you would solve this in any other language like C or VB or even Grasshopper. Hey Hannes! Thanks a lot! And I already see that some tasks are way easier to solve in GH than scripting them in Python but still It's all just about getting familiar with the python synthax So please excuse all my basic questions still to come. Sign Up or Sign In. Added by Parametric House 0 Comments 0 Likes. Added by Iman Sheikhansari 0 Comments 1 Like.

Added by Iman Sheikhansari 0 Comments 2 Likes. Powered by. Grasshopper algorithmic modeling for Rhino. Home Members Listings Ideas. Current Discussions Legacy Forum. All Discussions My Discussions. Share Tweet Facebook Facebook Views: Replies to This Discussion Permalink Reply by Raul Matagringo on December 5, at am Hey, if you have every time this 2 lists -one even, one odd-you can use the "Sort" component to put them together.

Put the two lists together, sort and output. Hope this helps, R. By omitting the 2 obvious wayshere's 5 "other" ways to skin the cat but it's C not Python.

But which is best? You should go in "VB, C and Python" with your question. Moral: ride the Blade, what else? Hello maxK, I am nor sure whether my solution is good for you to learn.Given two linked lists, insert nodes of second list into first list at alternate positions of first list.

The nodes of second list should only be inserted when there are positions available. Use of extra space is not allowed Not allowed to create additional nodesi. Expected time complexity is O n where n is number of nodes in first list. The idea is to run a loop while there are available positions in first loop and insert nodes of second list by changing pointers.

Following are implementations of this approach. This article is contributed by Chandra Prakash. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above. Writing code in comment? Please use ide. Merge a linked list into another linked list at alternate positions Pairwise swap elements of a given linked list by changing links Given a linked list of line segments, remove middle points Construct a Maximum Sum Linked List out of two Sorted Linked Lists having some Common nodes Can we reverse a linked list in less than O n?

Since head of first list never changes. Node next. Python program to merge a linked list into another at. Linked list Node. Inserts a new Node at front of the list. Put in the data. Make next of new Node as head. Move the head to point to new Node.

Main function that inserts nodes of linked list q into p at. While there are available positions in p. Save next pointers. Function to print linked list. Driver program to test above functions. Since head of first list. Write temp. WriteLine. WriteLine "First Linked List:". WriteLine "Second Linked List:".

WriteLine "Modified first linked list:". WriteLine "Modified second linked list:".

Merge Two Sorted Lists in Python

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Load Comments.You need to use zip function to create a list of tuples. Those tuples will have elements from list 'a' and 'b'. Then you can use redude function or Numpy concatenate function to get the desired output. You can try the following approaches:. Questions Hot! Ask a Question. Python: merge two lists by putting their elements at alternate positions. I want to merge them and the output list should be [1,2,3,4,5,6,7,8,9,10].

Python 3 Programming Tutorial - List Manipulation

Any pythonic approach? Please log in or register to add a comment. Please log in or register to answer this question. Related questions Python: How to get the indices of several elements in a list or numpy array at once?

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Python | Merge list elements

Snow Theme by Q2A Market. Powered by Question2Answer.Some of the list operations are quite general and having shorthands without needing to formulate a multiline code is always required.

Wanting to construct the list consisting of all the alternate elements of the original list is a problem that one developer faces in day-day applications. Method 1 : Using list comprehension. Shorthand to the naive method, list comprehension provides a faster way to perform this particular task. In this method, all the indices which are not multiple of 2, hence odd are inserted in the new list.

Method 2 : Using enumerate This is just a variation to the list comprehension method but does the similar internal working as list comprehension but uses different variables to keep track of index along with its value.

Method 3 : Using Slice notation This the most pythonic and elegant way to perform this particular task and enhances to the full power of python. We can use the skip utility provided by slice to get the alternate elements from start to end in the list.

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Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below. Writing code in comment? Please use ide. Python code to demonstrate. Output: The original list : [1, 4, 6, 7, 9, 3, 5] The alternate element list is : [4, 7, 3]. Check out this Author's contributed articles. Load Comments.Sometimes, we require to merge some of the elements as single element in the list. This is usually with the cases with character to string conversion.

This type of task is usually required in the development domain to merge the names into one element. It works with Python2 only. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.

See your article appearing on the GeeksforGeeks main page and help other Geeks. Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below. Writing code in comment? Please use ide.

python merge two lists alternating

Python3 code to demonstrate. Python code to demonstrate. Recommended Posts: Python Merge List with common elements in a List of Lists Python Merge first and last elements separately in a list Python Merge list of tuple into list by joining the strings Python List value merge in dictionary Python Merge elements of sublists Python Merge two list of lists according to first element Python Selective Merge list every Nth position Python Selective Merge in String list Python Merge Range Characters in List Python Merge two lists into list of tuples Python Ways to merge strings into list Python Merge Python key values to list Python Sorting list of lists with similar list elements Python Replace elements in second list with index of same element in first list Python Subtract two list elements if element in first list is greater.

Check out this Author's contributed articles. Load Comments.If you find this content useful, please consider supporting the work by buying the book! One essential feature offered by Pandas is its high-performance, in-memory join and merge operations. If you have ever worked with databases, you should be familiar with this type of data interaction. The main interface for this is the pd.

For convenience, we will start by redefining the display functionality from the previous section:. The behavior implemented in pd. The strength of the relational algebra approach is that it proposes several primitive operations, which become the building blocks of more complicated operations on any dataset. With this lexicon of fundamental operations implemented efficiently in a database or other program, a wide range of fairly complicated composite operations can be performed.

Pandas implements several of these fundamental building-blocks in the pd. As we will see, these let you efficiently link data from different sources. The pd.

All three types of joins are accessed via an identical call to the pd. Here we will show simple examples of the three types of merges, and discuss detailed options further below.

As a concrete example, consider the following two DataFrames which contain information on several employees in a company:. To combine this information into a single DataFramewe can use the pd. The result of the merge is a new DataFrame that combines the information from the two inputs.

Notice that the order of entries in each column is not necessarily maintained: in this case, the order of the "employee" column differs between df1 and df2and the pd.

Many-to-one joins are joins in which one of the two key columns contains duplicate entries. For the many-to-one case, the resulting DataFrame will preserve those duplicate entries as appropriate. Consider the following example of a many-to-one join:. The resulting DataFrame has an aditional column with the "supervisor" information, where the information is repeated in one or more locations as required by the inputs.

Many-to-many joins are a bit confusing conceptually, but are nevertheless well defined. If the key column in both the left and right array contains duplicates, then the result is a many-to-many merge.

This will be perhaps most clear with a concrete example. Consider the following, where we have a DataFrame showing one or more skills associated with a particular group.

python merge two lists alternating

By performing a many-to-many join, we can recover the skills associated with any individual person:. These three types of joins can be used with other Pandas tools to implement a wide array of functionality. But in practice, datasets are rarely as clean as the one we're working with here. In the following section we'll consider some of the options provided by pd. We've already seen the default behavior of pd.

python merge two lists alternating

However, often the column names will not match so nicely, and pd. Most simply, you can explicitly specify the name of the key column using the on keyword, which takes a column name or a list of column names:. This option works only if both the left and right DataFrame s have the specified column name.

At times you may wish to merge two datasets with different column names; for example, we may have a dataset in which the employee name is labeled as "name" rather than "employee". The result has a redundant column that we can drop if desired—for example, by using the drop method of DataFrame s:. Sometimes, rather than merging on a column, you would instead like to merge on an index.

For example, your data might look like this:.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I have two lists, the first of which is guaranteed to contain exactly one more item than the second. I would like to know the most Pythonic way to create a new list whose even-index values come from the first list and whose odd-index values come from the second list.

There's a recipe for this in the itertools documentation :. I know the questions asks about two lists with one having one item more than the other, but I figured I would put this for others who may find this question. Here is Duncan's solution adapted to work with two lists of different sizes.

This one is based on Carlos Valiente's contribution above with an option to alternate groups of multiple items and make sure that all items are present in the output :. Might be a bit late buy yet another python one-liner. This works when the two lists have equal or unequal size. One thing worth nothing is it will modify a and b. If it's an issue, you need to use other solutions.

Multiple one-liners inspired by answers to another question :. Learn more. Pythonic way to combine two lists in an alternating fashion? Ask Question. Asked 9 years, 7 months ago.

Active 12 days ago. Viewed 60k times. What's the most Pythonic approach? Not a duplicate! The accepted answer in the above-linked article produces a list of tuples, not a single, merged list.

Paul: Yes, the accepted answer does not give the complete solution. Read the comments and the other answers.


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