concatenate string in for loop python

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I need to concatenate strings in the list and add the integers to a sum; of course, I intend to change it to other data types later - thanks so much for all your kind responses, I am just getting the '0' output that was initialized in the beginning as if it skipped over the for loop :), Taking your statements literally (that you only want integers, not numerics) the entire program comes down to two function calls with filtered versions of the list. concatenation (+) operator Naive Method List Comprehension extend () method '*' operator itertools.chain () method 1. In this short tutorial, we'll take a look at how to concatenate strings in Python, through a few different approaches. The code is probably working perfectly. February 23, 2021 by Bijay Kumar In this python tutorial, we will discuss the Python concatenate arrays and also we will cover these below topics: How to concatenate arrays in python Python concatenate arrays in list Python concatenate arrays horizontally Python concatenate array vertically Python concatenate arrays to matrix This is what I have so far a = [3, 4, 6] temp = [] for i in a: query = 'Case:' + str (i) temp.append (query) print (' OR '.join (temp)) >>> Case:3 OR Case:4 OR Case:6 Is there a better way to write this? Python: Concatenate a String and Int (Integer) datagy Is a dropper post a good solution for sharing a bike between two riders? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Perform a quick search across GoLinuxCloud. Why add an increment/decrement operator when compound assignnments exist? If you have a list of strings and you want to concatenate them to create a single string made of these elements, you can use the For loop. As it is now, it will always add the string once more. first {} will be filled by var1 while the next {} will be filled by var2. String Concatenation Loops Avoiding dots. In Python, a string is a list of characters, which means that the + operator can be used to add their constituent elements together in a new list: This operator doesn't limit the amount of strings which can be added together, so you can easily join a large number of strings: Though, if your aim is to construct a sentence from a list of strings such as this, concatenating them manually, and without special characters is both inefficient and produces an unintelligible output: It'd be much more sensible to iterate through a list of strings, and add them together with a whitespace between each concatenated string: A shorthand operator you can use to concatenate two strings is +=, just like in the previous example. (You can do this with the <> button after highlighting your code or by making sure every line starts with 4 spaces.) Now, with each pass, there is a word and comma added to the end of the string. In Python, we can concatenate literal strings by simply placing them next to each other, without any operator or function. How alive is object agreement in spoken French? This approach is commonly used only for printing, since assigning it to an object in memory is easy, but awkward: If you'd like to avoid using whitespaces in the strings, you can add commas (,) between each element: If you'd like to assign them to a variable, you're free to do so, and they'll automatically be concatenated into a single string: You can even do multi-line strings. See below for all the approaches. Please put your code in a code section. If you do it in a for loop, its going to be inefficient as string addition/concatenation doesnt scale well (but of course its possible): Do comment if you have any doubts and suggestions on this Python for loop topic. How can I remove a mystery pipe in basement wall and floor? Python3 In some cases, these terms are absolutely interchangeable. You can convert it to the required output by chaining it to a, I took his code from above and split the converting and joining in two parts like in his code. In your code, you are always returning s, the string the user entered. By adding % in a string as a marker, we can replace the markers with concrete strings later on: Check out our hands-on, practical guide to learning Git, with best-practices, industry-accepted standards, and included cheat sheet. Why add an increment/decrement operator when compound assignnments exist? Local Variables Initializing Dictionary Elements Import Statement Overhead Data Aggregation Doing Stuff Less Often Python is not C Use xrange instead of range Re-map Functions at runtime Profiling Code Profiling The cProfile Module Trace Module Visualizing Profiling Results Now the above example can be confusing when you have to concatenate multiple strings. Morse theory on outer space via the lengths of finitely many conjugacy classes. How does the inclusion of stochastic volatility in option pricing models impact the valuation of exotic options? Method 1: String Concatenation using + Operator It's very easy to use the + operator for string concatenation. Using the % operator, we can perform string interpolation. Python string concatenation in for-loop in-place? You can choose either of the methods explained here but in case you have a long queue in some loop then you may want to choose wisely without impacting the performance. How can I remove a mystery pipe in basement wall and floor? And that return will cause the function so say: 'Hey, I'm done. Starting with Python 3.6 now we can use f-strings which is the recommended way of formatting strings. PythonSpeed/PerformanceTips - Python Wiki 2 Answers Sorted by: 2 how about: string = '' for i in range (end, -1, -1): string += phrase [i] print string However, an easier, cleaner way without the for loop is: print phrase [::-1] # this prints the string in reverse And also there is: What does that mean? A nicer way to do something about equivalent to your third method is, Why on earth are people paying for digital real estate? Spying on a smartphone remotely by the authorities: feasibility and operation, Travelling from Frankfurt airport to Mainz with lot of luggage. So, if we want to concatenate 2 lists, we will use for loop to iterate over each element in the list. In this we iterate for all strings and perform concatenation of values of range of each string. (Ep. My manager warned me about absences on short notice. This rule finds code that performs string concatenation in a loop using the + operator. So if the result has n characters the time complexity would be O(n^2), "Some later implementations of the Python interpreter have developed an optimization to allow such code to complete in linear time,..". python string string-concatenation Share Improve this question Follow There are multiple ways to concatenate strings. It involves joining two or more strings to create a single new string. Now, let us see how to concatenate strings in python, how to concatenate two strings in python. Python String Concatenation - GeeksforGeeks Same goes for "while-loop" or "palindrome". Another common way to concatenate strings in Python is by using the + operator. However, we also specified. How to concatenate string variables in Bash. Python string concatenation in for-loop in-place? We can also use str.join() method to join two strings using a delimiter. How do I concatenate two lists in Python? How do I concatenate strings in a while loop? 587), The Overflow #185: The hardest part of software is requirements, Starting the Prompt Design Site: A New Home in our Stack Exchange Neighborhood, Temporary policy: Generative AI (e.g., ChatGPT) is banned, Testing native, sponsored banner ads on Stack Overflow (starting July 6), How to concatenate strings and integer in a variable, Concatenating string and integer in Python. Is there a distinction between the diminutive suffices -l and -chen? To concatenate, or combine, two strings you can use the + operator. In terms of performance, this method is most recommended to concatenate strings. Is it an optimization which is in the latest python builds? Method 1: Python Concatenate List using append () method One of the most common ways to concatenate lists in Python is by using the append () method. If you run this code, you are going to get this result. @user1767754 First one still has syntax error in first line. For example: s1 = 'String' s2 = s1 + ' Concatenation' print (s2) Code language: PHP (php) Output: And you should consider using raw_input() because the normal input() will obly allow entering integers, like this: You should notice, that the statement a += s is the same as a = a + s. Next, the input message in your loop will probably distract the user a lot, when he is entering his strings. 08-31-2021 12:59 PM This is a simple example, and I'm sure there are better ways to do it, but when this gets more complex, I will be needing to append to the end of a string every 'loop' of the ForAll (). Python Strings Slicing Strings Modify Strings Concatenate Strings Format Strings Escape Characters String Methods String Exercises. These two facts can help you learn (and then remember) how to use .split (). Method-1: Concatenate strings using .format () Example-1: Using default placeholders Example-2: Using positional arguments Example-3: Using f-strings Method-2: Using + operator Example-1: Concatenating strings Example-2: Concatenating string with integers Method-3: Append strings using += operator Example-1: Join two block of sentences Thanks for contributing an answer to Stack Overflow! Append String in a Loop in Python If you have a list of strings and you want to concatenate them to create a single string made of these elements, you can use the For loop. In Python, you can concatenate strings using the + operator. How to reverse a string in Python - PythonForBeginners.com To learn more, see our tips on writing great answers. rev2023.7.7.43526. Once we execute the above Python program, we will get the following result. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing. How do countries vote when appointing a judge to the European Court of Justice. Using For loop in the string you can iterate over characters of a string in Python. How much space did the 68000 registers take up? I generated the script to test the join vs += performance for some randomly generated data and found that for 100,000 strings of length up to ten characters, join is maybe 20% faster than using +=. where we have defined the entire sentence under f'' while the individual variables are defined under {}. This solution is specific to removing individual characters though. We can easily fix that inside the loop. Here is an example of using the join() method to concatenate Python Strings. Python For Looping Through a String - W3Schools It initializes 3 variables. However, the arguments must be a string. Get tutorials, guides, and dev jobs in your inbox. All these changes in one piece of code will look like this: I am answering this on my mobile, so please excuse any mistakes. the problem is that, for example user's input is hello, the comma(,) in the last line of the code makes the output to be o l l e h, but if there isnt a comma there, the output will have each letter in a line. The neuroscientist says "Baby approved!" Let's add some integers to our strings list and box all of the items with a str() in case there are non-string elements: If you want to create a new string by replicating a string n amount of times and appending it, you can achieve this with the * operator: This can be even more useful when combined with the + operator: Again, concatenation doesn't necessarily mean we're adding a string to the end. Python String Concatenation in for loop long strings [duplicate]. Why is char[] preferred over String for passwords? My question might be not clear, but i wanted to know if python is optimized for doing += or not. Your email address will not be published. 1 2 3 4 5 6 7 list_of_strings = ['one', 'two', 'three'] my_string = '' for word in list_of_strings: my_string += str(word) print("Final result:", my_string) Is religious confession legally privileged? The join() method takes an iterable as an argument and returns a string created by joining the elements of that iterable. In Python, f-string is short for formatted string literal and it is another way to format strings. It is that piece of code that I was looking for. Can Visa, Mastercard credit/debit cards be used to receive online payments? 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. We'll want it to be able to handle 2D lists as well, so if a list contains another list within itself - it's flattened to a 1-dimensional list, before joined: A simple way to concatenate strings, usually only when you're printing them is to leverage the space bar. Why do complex numbers lend themselves to rotation? One of the basic ways to concatenate the strings in Python is by using the comma (,). Can the Secret Service arrest someone who uses an illegal drug inside of the White House? Splitting, Concatenating, and Joining Strings in Python Similarly enough, you can use other markers for other data types: Note: If you wish to explicitly mark how many digits should the number be rounded to (say 2), you can achieve it with: %.2f. You can concatenate in any order, such as concatenating str1 between str2 and str3. Anyway.. enjoy.. One more option to append a string is using += operator. Example Get your own Python Server Merge variable a with variable b into variable c: a = "Hello" b = "World" c = a + b print(c) Try it Yourself Example To add a space between them, add a " ": a = "Hello" b = "World" c = a + " " + b print(c) Try it Yourself If you prefer to use the While loop, you need to create a counting variable and know how many words are there inside the list. I have shared multiple examples for individual methods which can help you understand the basics so you can implement them accordingly in your code. Let's see what this looks like: # Concatenating a String and an Int in Python with .format word = 'datagy' integer = 2022 new_word = ' {} {}'. Notify me via e-mail if anyone answers my comment. Python - String Concatenation - W3Schools By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. You can go on now.' Can I ask a specific person to leave my defence meeting? However, an easier, cleaner way without the for loop is: To concatenate something, you have to have a string to concatenate to. # concatenating strings using + operator, Python List vs Set vs Tuple vs Dictionary Comparison, # Append extra whitespace and var2 into var1, # Define variable with empty string value, # Join both var1 and var2 using fullstop Appending strings refers to appending one or more strings to the end of another string. The join() method is called on a string, gets passed a list of strings, and returns a string. To explain, I have this list: And inside a for loop I need to end with this: Can you give me a clue on how to achieve this in python? In this example we combine two strings using + operator. I have a list of integers and I want to concatenate them in a loop. How to passive amplify signal from outside to inside? Method #1 : Using join () + list comprehension The combination of above functions can help to get the solution to this particular problem in just a one line and hence quite useful. Method 1: Naive appending def method1 (): out_str = '' for num in xrange (loop_count): out_str += `num` return out_str To me this is the most obvious approach to the problem. Morse theory on outer space via the lengths of finitely many conjugacy classes. String concatenation in loop CodeQL query help documentation - GitHub Depending on the size of your document, different approaches will be faster. How do I concatenate strings in a while loop? Not the answer you're looking for? critical chance, does it have any reason to exist? Iterative '+' concatenation. You'll find several tools and techniques for concatenating strings in Python, each with its own pros and cons. 587), The Overflow #185: The hardest part of software is requirements, Starting the Prompt Design Site: A New Home in our Stack Exchange Neighborhood, Temporary policy: Generative AI (e.g., ChatGPT) is banned, Testing native, sponsored banner ads on Stack Overflow (starting July 6), Concatenating string outputs of a for loop in Python 3. Thanks everyone who answered! Efficient String Concatenation in Python - Real Python Have you guessed how those two features of strings relate to splitting functionality in Python? To learn more, see our tips on writing great answers. >>> ''.join ( ['first', 'second', 'other']) 'firstsecondother' Following example will help you understand this more clearly: Here if you notice f'Let us learn {var1}, it is absolutely {var2}!' Connect and share knowledge within a single location that is structured and easy to search. It is possible? How to concatenate to a string in a for loop in Python? the net result is the same.. :). So if the result has n characters the time complexity would be O (n^2) Bad: runs in O (n^2). Not the answer you're looking for? python - Concatenating in for loop - Stack Overflow Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Thanks for contributing an answer to Stack Overflow! 4 Answers Sorted by: 4 Here's what I assume you're trying to do: def add_words (): a = '' s = 'a' while s != '': s = input ("I will echo your input until you enter return only: ") a += s # equivalent to a = a + s # we exit the code block when they enter the empty string return a But really you should do it like this: Here we defined 2 string-type variables and then we used the plus (+) operator to concatenate the strings. Answer: Use the join function to concatenate string. I deleted my answer. Identifying large-ish wires in junction box. What is the verb expressing the action of moving some farm animals in a field to let them eat grass or plants? 15amp 120v adaptor plug for old 6-20 250v receptacle? How do I split the definition of a long string over multiple lines? I need to do it in a for loop, I need to add some logic inside a for loop. However, to get a 10-fold speed increase on both str.join and += then use str.translate. Here is an example of using comma (,) to concatenate strings in Python. All rights reserved. Book or a story about a group of people who had become immortal, and traced it back to a wagon train they had all been on. Can you work in physics research with a data science degree? Let's take a look at an example: I didn't know. The format() is a built-in function in Python utilized to format strings. ), and you are required to use a for loop then what will work (although is not pythonic, and shouldn't really be done this way if you are a professional programmer writing python) is this: You don't need the 'prints', I just threw them in there so you can see what is happening. Examples: Input : test_list = ['gfg', 'for', 'all', 'geeks'], Output : gfoallgeek Explanation : g, fo, all, geek -> concatenated from each string [ increasing order ]. ), it may make sense to pull the string construction out of the loop or create the transformed elements and then apply this to concat them. Additionally, a separator is used to define the separator between the joined strings, and it's the base string we call join() on: In a lot of cases, the separator is just a whitespace, so you'll commonly be seeing: Since the built-in join() method might behave a bit differently than you might've expected, let's implement our own join() method with an adjustable separator. With each pass of the loop, the next word is added to the end of the string. An example of using the += operator on strings is given below. Is there a legal way for a country to gain territory from another through a referendum? There are several ways to concatenate dictionaries in Python, including using the update () method, the ** operator, and the chain () method from the itertools module and etc. So I'm trying to make it so I can type multiples strings and it will concatenate all of them. Connect and share knowledge within a single location that is structured and easy to search. - Stack Overflow Python - How to concatenate to a string in a for loop? They are probably just teaching it the way they would teach C++. Here is the list of 8 methods that we have covered in this tutorial. What is the verb expressing the action of moving some farm animals in a field to let them eat grass or plants? 587), The Overflow #185: The hardest part of software is requirements, Starting the Prompt Design Site: A New Home in our Stack Exchange Neighborhood, Temporary policy: Generative AI (e.g., ChatGPT) is banned, Testing native, sponsored banner ads on Stack Overflow (starting July 6), Python: the mechanism behind list comprehension, Comparing list comprehensions and explicit loops (3 array generators faster than 1 for loop). Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing. Apart from SharePoint, I started working on Python, Machine learning, and artificial intelligence for the last 5 years. Not quite sure how to do that since I'm not able to set a variable inside of it. I will be using following Python version to demonstrate all the examples: You can learn more about this method of formatting at 10+ simple examples to use Python string format in detail. Can Visa, Mastercard credit/debit cards be used to receive online payments? Therefore, remove all of the returns im your loop, as you don't want to end the function while the user is still entering their strings. In the example, we used two string-type variables myvar1 and myvar2. Cannot assign Ctrl+Alt+Up/Down to apps, Ubuntu holds these shortcuts to itself. Thanks for your reply. To concatenate a string to an integer you have to convert the integer into a string using the str () function that returns the string version of a Python object. Yes, you can use generator expression and str.join . To subscribe to this RSS feed, copy and paste this URL into your RSS reader. In the above example, we used the concept of concatenating literal strings on New and Zealand strings together. No spam ever. During this time I got expertise in various Python libraries also like Tkinter, Pandas, NumPy, Turtle, Django, Matplotlib, Tensorflow, Scipy, Scikit-Learn, etc for various clients in the United States, Canada, the United Kingdom, Australia, New Zealand, etc. All the statements after the return statements won't get called and your program will jump out of the loop directly. Enthusiasm for technology & like learning technical. How do countries vote when appointing a judge to the European Court of Justice? Copyright 2014EyeHunts.com. Why do keywords have to be reserved words? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. It's worth noting that strings in Python are immutable - a string object in memory cannot be changed once created: If you'd like to change this string in any way - under the hood, a new string with those changes is created. In the example, we concatenated the United string with States using the format() function. [duplicate] Ask Question Asked 11 years, 7 months ago Modified 11 years, 7 months ago Viewed 238k times 28 This question already has answers here : Most Pythonic way to concatenate strings (6 answers) Closed 9 years ago. This saves you from the trouble of having to create a new variable to store the results, as you can reuse one of the existing reference variables to assign to the new object in memory: The main limitation of the + operator is the fact that you can't mix-and-match types. Is the part of the v-brake noodle which sticks out of the noodle holder a standard fixed length on all noodles? If you observe, I have added an extra space 'Let us learn ' to handle the extra whitespace as + operate will concatenate the string in between the text but it will not add extra space unless the variable is defined in that way. Let us look at an example of this in Python. Didn't find what you were looking for? Asking for help, clarification, or responding to other answers. str1 = "Hello" str2 = "World" result = str1 + " " + str2 print (result) # Output: Hello World. rev2023.7.7.43526. Book or a story about a group of people who had become immortal, and traced it back to a wagon train they had all been on. Here an example: Finally, one thing to optimize would be your condition to end the loop. Find centralized, trusted content and collaborate around the technologies you use most. Is there a deep meaning to the fact that the particle, in a literary context, can be used in place of , Python zip magic for classes instead of tuples. Is the time-complexity of iterative string append actually O(n^2), or O(n)? In most other programming languages, if we concatenate a string with an integer (or any other primitive data types), the language takes care of converting them to a string and then concatenates it. Required fields are marked *. Reverse string using slicing The first and easiest way to reverse a string in python is to use slicing. String concatenation is the process of combining two or more strings into a single string. Method #1 : Using loop + string slicing This is brute way in which this task can be performed. This is what I am looking for. So I am using += operator to add the content of var2 with a whitespace in var1 variable. So unless you have lots of small documents stick with str.join. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. I am Bijay Kumar, a Microsoft MVP in SharePoint. str.translate doesn't need to do this and so is much faster. And a strange comment. 6 Ways to Concatenate Lists in Python | DigitalOcean Yes, we can add or concatenate strings. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing, @iCodez ooh that's way nicer. Issue with a string concatenating during while loop Python, Python: concatenate string and int in a loop, String concatenation in while loop not working, Append to a string with characters in a while loop python. You can also use map and lambda expressions: Completing the idea from @Joshua K for using map and lambda (although I think the list comprehension is a better solution): Thanks for contributing an answer to Stack Overflow! With this function, we used the placeholders as curly brackets, and the format() function replaces the given string with the placeholders. However, thats not neccessary for your code to work, obviously. Note: IDE:PyCharm2021.3.3 (Community Edition). There's much more to know. Why on earth are people paying for digital real estate? Do I have the right to limit a background check? Why did Indiana Jones contradict himself? At first, you should write the most readable code for you; only if you have issues with the runtime, you should think of optimization: For current CPython implementations join is faster than '+'. Do I have the right to limit a background check? Here's what I assume you're trying to do: And when you learn itertools magic you could make something (admittedly ugly) like Issue with your code is, you did not put proper break condition, rather your just returned after reading first input item. @Andr Depending on the logic you need (some transformation to the elements? Concatenate Strings in Python [With Examples] - Codefather Append String in a Loop in Python - Codeigo By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. ', Python delete file Examples [4 Different Ways], # I have handled extra whitespace under quotes and then Here is an example of this approach in Python. Unsubscribe at any time. Although you have to handle any extra spaces inside the string quotes.