For Python str.rfind(sub[, start[, end]]) method, I think these are the default values for the start and end parameters: start = 0 end = the index of the last character of the string, which is equivalent to the length of the string minus 1. However, Python returns different results for lines 3 and 4 below.… Read More Why does Python return -1 for string.rfind(last character of string, 0, len(string) – 1)?
Suppose this dataframe: col1<- c(‘a_b_c_fv’, ‘ff_g1_h_fv’,’e_ii_jjjj_fv’ ) df <- data.frame(col1) Want to find the location of the third occurrence of the underscore _ and then write that location back to the data frame. So final result would look like: df$location <- c(6,8,10) How can I do this pleaase? I have tried unlist(gregexpr(‘_’, df$col1))[3] but I… Read More Find location of a character and write location to a data frame in r
I am currently working on a program that prompts the user to input their favorite color, and then asks them to give them a position of a character within the given color. The program will then take that given number and find the character. (ie, input Yellow as the color, and the put 2 as… Read More Find a character in a string from a given integer?
Im trying to create some #define in c++, but now im stuck in this part #include<bits/stdc++.h> #define FASTRW ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0) #define IO(filename) freopen(filename + ".inp", "r", stdin); freopen(filename + "out", "w", stdout) using namespace std; int main(){ FASTRW; IO("lmao"); return 0; } the first define worked just fine, but my vs code showed the… Read More How to define a macro that take the file's name and read, write to same name but different extensions using freopen()
There is code: #include <stdio.h> #include <string.h> #include <stdlib.h> int main() { char *str = calloc(3, sizeof(char)); str[2] = ‘\0′; printf("%ld", strlen(str)); free(str); } Expected output 2 Actual output 0 Why? As far as I understood strlen counts symbols before \0. Maybe str[0] and str[1] are already ‘\0’? >Solution : calloc() initializes allocated memory with… Read More Why NULL terminated string's length is smaller than expected in C?
I have the following string with placeholders ‘test {{1}} this {{2}} {{3}}’ these placeholders later should be replaced in same order by the values from input fields [‘now’, ‘code’, ‘block’] so the final string looks like this ‘test now this code block’ what’s the best approach here? >Solution : You can use .replace() on your… Read More Replace words in string with values of string array
I have the following vector vector <- c(31, 41, 51, 61, 32, 42, 52, 62, 33, 43, 53, 63, 34, 44, 54, 64, 35, 45, 55, 65, 36, 46, 56, 66) I would like just to replace the leading number without convert that number when it is found as unit digit str_replace_all(vector, c(‘3’ = ‘Air’,… Read More How replace just leading number for a string where those characters appear also as unit
The original code prints the msg in the brackets, but the second code prints just Hey there. Why is this? I started C++ a few days ago. Have experience in Python and some C#. Original code:- #include <iostream> #include <vector> #include <string> using namespace std; int main() { vector<string> msg {"Hello", "C++", "World", "from", "VS… Read More Why doesn't this line print after I replace this?
The original code prints the msg in the brackets, but the second code prints just Hey there. Why is this? I started C++ a few days ago. Have experience in Python and some C#. Original code:- #include <iostream> #include <vector> #include <string> using namespace std; int main() { vector<string> msg {"Hello", "C++", "World", "from", "VS… Read More Why doesn't this line print after I replace this?
I have a string with Unicodes inside of it, and I am trying to extract each unicode from the overall string and save it to a list/array.. This is the overall string: "test 🔷 test 💙 test 🔹" I want the following list: 1. 🔷 2. 💙 3. 🔹 Right now I am trying the… Read More How to take specific set of characters out of overall string and save to array or list?