range | 易学教程

Why do I not have to define the variable in a for loop using range(), but I do have to in a while loop in Python?

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问题 I have the following code using a for loop: total = 0 for num in range(101): total = total + num print(total) Now the same result using a while loop: num = 0 total = 0 while num <= 99: num = num + 1 total = total + num print(total) Why is it that I do not have to define num in the first case, but I do have to define it in the second? Are they both not variables? 回答1: I'd like to approach this question from a slightly different perspective. If we look at the official Python grammar

how to construct a apache commons 3.1 Range<Integer> object

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问题 How can I create a apache commons 3.1 Range object? The java docs say: " An immutable range of objects from a minimum to maximum point inclusive. " " The objects need to either be implementations of Comparable or you need to supply a Comparator. " But when I try: Range<Integer> range = new Range<Integer>(100, 200); I get an error in my IDE that says required arguments are Integer, Integer, comparator. Even though Integer implements the Comparable interface and thus I shouldn't need a extra

Generate random number of certain amount of digits

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问题 Hy, I have a very Basic Question which is : How can i create a random number with 20 digits no floats no negatives (basically an Int) in Swift ? Thanks for all answers XD 回答1: Here is some pseudocode that should do what you want. generateRandomNumber(20) func generateRandomNumber(int numDigits){ var place = 1 var finalNumber = 0; for(int i = 0; i < numDigits; i++){ place *= 10 var randomNumber = arc4random_uniform(10) finalNumber += randomNumber * place } return finalNumber } Its pretty

Python - Unsupported type(s) : range and range

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问题 I'm getting this strange error trying to run a script, the code appears to be correct but it seems python (3) didn't liked this part: def function(x): if integer: return int(x) else: return x non_nil = randrange(21) d = dict([(randrange(101), Racional(coeff(randrange(-20,20)), coeff(choice(range(-30,0)+\ range(1,30))))) for k in range(non_nil)]) And i get the following error: for k in range(non_nil)]) unsupported operand type(s) for +: 'range' and 'range' I already tried to put the last four

Run Time Error 1004 'Unable to get the PivotFields property of the PivotTable class'

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I realy have no Idea what this error means... I am trying to use the code to select all the rows under one of the subheaders in a pivot table. I am getting a run time error 1004 "unable to get the PivotFields property of the Pivot Table class". Here is the code: Sub ttest() Dim pt As PivotTable Set pt = Sheets("Report").PivotTables("PivotTable1") pt.PivotFields("Row Labels").PivotItems("CL").DataRange.Select End Sub ib11 As JosieP said in the comments, the 1004 error means that there is no such object , that is there is no such pivot field that is called "Row Labels". 来源： https://stackoverflow

Define multiple ranges in Google Apps Script

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问题 I'm having difficulty defining multiple ranges in GAS. I have the following simple function I need to perform: var dataRange = sheet.getRange(checkRange); var values = dataRange.getValues(); for (var i = 0; i < values.length; i++) { for (var j = 0; j < values[i].length; j++) { if (values[i][j] == false) { values[i][j] = true; } } } dataRange.setValues(values); My range is actually defined by another function: var checkRange = []; for(var i = 0; i<checkboxes.length; i++) { if(checkboxes[i]) {

C++ - Finding intersection of two ranges

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What is the best way to find the intersection of two ranges in C++? For example, if I have one range as [1...20] inclusive, and another as [13...45] inclusive, I want to get [13...20], as that is the intersection between them. I thought about using the native set intersection function in C++, but I would first have to convert the range into a set, which would take too much computation time for large values. intersection = { std::max(arg1.min, arg2.min), std::min(arg1.max, arg2.max) }; if (intersection.max < intersection.min) { intersection.markAsEmpty(); } yau For the sake of completeness I

Comparing NumPy arange and custom range function for producing ranges with decimal increments

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问题 Here's a custom function that allows stepping through decimal increments: def my_range(start, stop, step): i = start while i < stop: yield i i += step It works like this: out = list(my_range(0, 1, 0.1)) print(out) [0, 0.1, 0.2, 0.30000000000000004, 0.4, 0.5, 0.6, 0.7, 0.7999999999999999, 0.8999999999999999, 0.9999999999999999] Now, there's nothing surprising about this. It's understandable this happens because of floating point inaccuracies and that 0.1 has no exact representation in memory.

Are there any C++ language obstacles that prevent adopting D ranges?

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This is a C++ / D cross-over question. The D programming language has ranges that -in contrast to C++ libraries such as Boost.Range - are not based on iterator pairs. The official C++ Ranges Study Group seems to have been bogged down in nailing a technical specification. Question : does the current C++11 or the upcoming C++14 Standard have any obstacles that prevent adopting D ranges -as well as a suitably rangefied version of <algorithm> - wholesale? I don't know D or its ranges well enough, but they seem lazy and composable as well as capable of providing a superset of the STL's algorithms.

JavaScript convert mouse position to selection range

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I would like to be able to convert the current mouse position to a range, in CKEditor in particular. The CKEditor provides an API for setting the cursor according to a range: var ranges = new CKEDITOR.dom.range( editor.document ); editor.getSelection().selectRanges( [ ranges ] ); Since CKEditor provides this API, the problem may be simplified by removing this requirement and just find a way to produce the range from the mouse coordinates over a div containing various HTML elements. However, this is not the same as converting a mouse coordinate into the cursor position in a textarea since