How do you start a loop from a specified index in python?
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What is the best way to set a start index when iterating a list in Python. For example, I have a list of the days of the week - Sunday, Monday, Tuesday, ... Saturday - but I want to iterate through the list starting at Monday. What is the best practice for doing this? Show asked May 27, 2011 at 6:28
Vincent CatalanoVincent Catalano 2,1794 gold badges21 silver badges29 bronze badges 3
You can use slicing: This will start at the third element and iterate to the end. answered May 27, 2011 at 6:31
Björn PollexBjörn Pollex 73.4k28 gold badges192 silver badges276 bronze badges 8
answered May 27, 2011 at 6:49
John La RooyJohn La Rooy 285k50 gold badges358 silver badges498 bronze badges You can always loop using an index counter the conventional C style looping: It is always better to follow the "loop on every element" style because that's the normal thing to do, but if it gets in your way, just remember the conventional style is also supported, always. answered May 27, 2011 at 6:35
Why are people using list slicing (slow because it copies to a new list), importing a library function, or trying to rotate an array for this? Use a normal for-loop with For example, looping through an array starting at index 1: answered Jul 14, 2020 at 20:05
Charlie SuCharlie Su 3283 silver badges7 bronze badges 1 stdlib will hook you up son!
Björn Pollex 73.4k28 gold badges192 silver badges276 bronze badges answered May 27, 2011 at 9:16
synthesizerpatelsynthesizerpatel 26.6k5 gold badges72 silver badges90 bronze badges If all you want is to print from answered May 27, 2011 at 7:17
juanchopanzajuanchopanza 219k31 gold badges390 silver badges464 bronze badges 1 Here's a rotation generator which doesn't need to make a warped copy of the input sequence ... may be useful if the input sequence is much larger than 7 items. answered May 27, 2011 at 8:52
John MachinJohn Machin 79.4k11 gold badges138 silver badges183 bronze badges 2 If you want to "wrap around" and effectively rotate the list to start with Monday (rather than just chop off the items prior to Monday): answered May 27, 2011 at 8:19
slothropslothrop 1,0176 silver badges7 bronze badges Loop whole list (not just part) starting from a random pos efficiently: answered Feb 2 at 19:52
How do you start a loop at a specific index in Python?Use slicing to start a for loop at index 1
Use slice notation [start:] with start as 1 to create a copy of the sequence without the element at index 0 . Iterate over the sliced sequence. To start the loop at an element at a different index, set start to the desired index.
How do you use the loop index in Python?To check the index in for loop you can use enumerate() function. In Python, the enumerate() is an in-built function that allows us to loop over a list and count the number of elements during an iteration with for loop. There are various method to check how to check the index in for loop in Python.
How do I loop a second index in Python?If you want to iterate through a list from a second item, just use range(1, nI) (if nI is the length of the list or so). i. e. Please, remember: python uses zero indexing, i.e. first element has an index 0, the second - 1 etc. By default, range starts from 0 and stops at the value of the passed parameter minus one.
How do you start writing a loop in Python?Let's go over the syntax of the for loop: It starts with the for keyword, followed by a value name that we assign to the item of the sequence ( country in this case). Then, the in keyword is followed by the name of the sequence that we want to iterate. The initializer section ends with “ : ”.
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