arrays

问题 I am writing a program to do some analysis on DNA sequences. Everything works fine except for this thing. I want to declare a 2D array of size m*n where m and n are read from an input file. Now the issue is that if m and n goes too large. As an example if m = 200 and n = 50000 then I get a seg fault at the line where I declare my array. array[m][n]; Any ideas how to overcome this. I do need such an array as my entire logic depends on how to process this array. 回答1: Probably you are running

问题 I have a bash command that outputs text in the following format: Header 1 - Point 1 - Point 2 Header 2 - Point 1 - Point 2 Header 3 -Point 1 - Point 2 ... I want to parse this text into an array, separating on the empty line so that array[0] for example contains: Header 1 - Point 1 - Point 2 And then I want to edit some of the data in the array if it satisfies certain conditions. I was looking at something like this Separate by blank lines in bash but I'm completely new to bash so I don't

问题 [{name: "mode", value: "1"},{name: "group", value: ""},{name: "from_date", value: ""},{name: "to_date", value: "2018-10-16"},{name: "action", value: "ac_filter_transactions"} This is how my array looks like. I want to remove the name and value pair from the array if the value is empty. I tried this solution: but this didn't work formData.map((i) => { (i.value == "") ? delete i: ""; }); I know this is a simple question but I couldn't find any relevant example to solve this problem. All

问题 I tried to get the inputs(strings) from user and store them in an array.But after I ran this code, the program instantly crashed. #include <stdio.h> int main() { int i; char *word[3]; for(i=0;i<3;i++) { printf(" Enter a word: "); scanf("%s", &word[i]); } printf("%s ", word[0]); return 0; } 回答1: In this line: scanf("%s", &word[i]); You need to make sure word[i] is pointing somewhere, and has enough space to occupy the string entered. Since word[i] is a char * pointer, you need to at some time

问题 The following code will construct array of 10 Foo objects with default Foo constructor: Foo foo[10]; but i don't want do this, i have havy foo constructor and later i will regenarate all foo objects one by one and assign (copy) it to elements of foo array, so there is no sense to initialize array, i want just reserve space for it and set it elements later. Just like in the case of int foo[10] when elements of foo will not be initialized without ={}. How can i do this without using std

问题 If I have an Array Candy[] type; and type = new Candy[capacity]; if the Array is full is capacity = type.length ? 回答1: Since you are using array, the size of array is determined during compilation. Thus if your intention is to check whether current array's index has reached the last array element, you may use the following condtion (possibly in a loop) to check whether your current array index is the last element. If it is true, then it has reached the last element of your array. Example: int

问题 I want to be able to calculate the cumulative sum of a large n-dimensional numpy array. The value of each element in the final array should be the sum of all elements which have indices greater than or equal to the current element. 2D: xᶦʲ = ∑xᵐⁿ ∀ m ≥ i and n ≥ j 3D: xᶦʲᵏ = ∑xᵐⁿᵒ ∀ m ≥ i and n ≥ j and o ≥ k Examples in 2D: 1 1 0 2 1 0 1 1 1 -> 5 3 1 1 1 1 8 5 2 1 2 3 6 5 3 4 5 6 -> 21 16 9 7 8 9 45 33 18 Example in 3D: 1 1 1 3 2 1 1 1 1 6 4 2 1 1 1 9 6 3 1 1 1 6 4 2 1 1 1 -> 12 8 4 1 1 1 18

问题 If I have an Array Candy[] type; and type = new Candy[capacity]; if the Array is full is capacity = type.length ? 回答1: Since you are using array, the size of array is determined during compilation. Thus if your intention is to check whether current array's index has reached the last array element, you may use the following condtion (possibly in a loop) to check whether your current array index is the last element. If it is true, then it has reached the last element of your array. Example: int

问题 I know how to delete every 4th element in a numpy array: frame = np.delete(frame,np.arange(4,frame.size,4)) Now I want to know if there is a simple command that can delete every nth (e.g 4) times 3 values. A basic example: input: [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20....] Would lead to: output: [1,2,3,7,8,9,13,14,15,19,20,....] I was hoping for a simple numpy / python functionality, rather than writing a function that has to iterate over the vector (cause it is quite long in my

问题 I know how to delete every 4th element in a numpy array: frame = np.delete(frame,np.arange(4,frame.size,4)) Now I want to know if there is a simple command that can delete every nth (e.g 4) times 3 values. A basic example: input: [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20....] Would lead to: output: [1,2,3,7,8,9,13,14,15,19,20,....] I was hoping for a simple numpy / python functionality, rather than writing a function that has to iterate over the vector (cause it is quite long in my