comparison

问题 Thank you for your kind reply to my previous questions. I have two lists: list1 and list2. I would like to know if each object of list1 is contained in each object of list2. For example: > list1 [[1]] [1] 1 [[2]] [1] 2 [[3]] [1] 3 > list2 [[1]] [1] 1 2 3 [[2]] [1] 2 3 [[3]] [1] 2 3 Here are my questions: 1.) How do you I ask R to check if an object is a subset of another object in a list? For instance I would like to check if list2[[3]]={2,3} is contained in (subset of) list1[[2]]={2} . When

问题 I have two lists (of different lengths). One changes throughout the program ( list1 ), the other (longer) doesn't ( list2 ). Basically I have a function that is supposed to compare the elements in both lists, and if an element in list1 is in list2 , that element in a copy of list2 is changed to 'A', and all other elements in the copy are changed to 'B'. I can get it to work when there is only one element in list1 . But for some reason if the list is longer, all the elements in list2 turn to B

问题 I have two data frames with different size df1 YearDeci Year Month Day ... Magnitude Lat Lon 0 1551.997260 1551 12 31 ... 7.5 34.00 74.50 1 1661.997260 1661 12 31 ... 7.5 34.00 75.00 2 1720.535519 1720 7 15 ... 6.5 28.37 77.09 3 1734.997260 1734 12 31 ... 7.5 34.00 75.00 4 1777.997260 1777 12 31 ... 7.7 34.00 75.00 and df2 YearDeci Year Month Day Hour ... Seconds Mb Lat Lon 0 1669.510753 1669 6 4 0 ... 0 NaN 33.400 73.200 1 1720.535519 1720 7 15 0 ... 0 NaN 28.700 77.200 2 1780.000000 1780 0

问题 While reading the book Programming Principles and Practice Using C++ , in Chapter 3 it sates that we can;t directly compare a double to an int. However, when I tested it out on Visual Studios, it was running fine with no errors? What does he mean by not being able to compare double to an int. Later, he explains that C++ provides an indirect way. Does he mean implicit conversion? 回答1: C++ has a sets of built-in operators defined in [over.built]. The behavior of the equality operator is defined

问题 While reading the book Programming Principles and Practice Using C++ , in Chapter 3 it sates that we can;t directly compare a double to an int. However, when I tested it out on Visual Studios, it was running fine with no errors? What does he mean by not being able to compare double to an int. Later, he explains that C++ provides an indirect way. Does he mean implicit conversion? 回答1: C++ has a sets of built-in operators defined in [over.built]. The behavior of the equality operator is defined

问题 While reading the book Programming Principles and Practice Using C++ , in Chapter 3 it sates that we can;t directly compare a double to an int. However, when I tested it out on Visual Studios, it was running fine with no errors? What does he mean by not being able to compare double to an int. Later, he explains that C++ provides an indirect way. Does he mean implicit conversion? 回答1: C++ has a sets of built-in operators defined in [over.built]. The behavior of the equality operator is defined

问题 While reading the book Programming Principles and Practice Using C++ , in Chapter 3 it sates that we can;t directly compare a double to an int. However, when I tested it out on Visual Studios, it was running fine with no errors? What does he mean by not being able to compare double to an int. Later, he explains that C++ provides an indirect way. Does he mean implicit conversion? 回答1: C++ has a sets of built-in operators defined in [over.built]. The behavior of the equality operator is defined

问题 While reading the book Programming Principles and Practice Using C++ , in Chapter 3 it sates that we can;t directly compare a double to an int. However, when I tested it out on Visual Studios, it was running fine with no errors? What does he mean by not being able to compare double to an int. Later, he explains that C++ provides an indirect way. Does he mean implicit conversion? 回答1: C++ has a sets of built-in operators defined in [over.built]. The behavior of the equality operator is defined

问题 I am wondering if there is a way to do the following in a more compact style: if (text == "Text1" or text=="Text2" or text=="Text3" or text=="Text4"): do_something() The problem is i have more than just 4 comparisons in the if statement and it's starting to look rather long, ambiguous, and ugly. Any ideas? 回答1: How about this: if text in ( 'Text1', 'Text2', 'Text3', 'Text4' ): do_something() I've always found that simple and elegant. 回答2: The "if text in" answer is good, but you might also

问题 I recently answered a SO-question about using -lt or -gt with strings. My answer was based on something I've read earlier which said that -lt compares one char from each string at a time until a ASCII-value is not equal to the other. At that point the result (lower/equal/greater) decides. By that logic, "Less" -lt "less" should return True because L has a lower ASCII-byte-value than l , but it doesn't: [System.Text.Encoding]::ASCII.GetBytes("Less".ToCharArray()) 76 101 115 115 [System.Text