for-loop

问题 It's been a while since I've done intense bash scripting and I forgot the syntax for doing multiple conditions in a for loop. In C, I'd do: for(var i=0,j=0; i<arrayOne.length && j<arrayTwo.length; i++,j++){ // Do stuff } I've been googling for a while and have only found syntax involving nested for loops, not multiple conditions to one for loop. 回答1: Sounds like you're talking about the arithmetic for loop . for ((i = j = 0; i < ${#arrayOne[@]} && j < ${#arrayTwo[@]}; i++, j++)); do # Do

问题 def strange_syntax(stuff): return ".".join(item for item in stuff) How (and why) works this code? What happens here? Normally I can't use this syntax. Also, this syntax doesn't exist if it's not inside some function as an argument. I know, I could do the same with: def normal_syntax(stuff): return ".".join(stuff) 回答1: When used in a function call, the syntax: f(a for a in b) implicitly is compiled as a generator, meaning f((a for a in b)) This is just syntactic sugar, to make the program look

问题 Hi I am trying to split the values in a (y2) list into (inv) amount of parts. x = [0,100,200,300,400,500,600,700,800,900,1000,1100] y2 = [58,55,49,12,6,5,4,4.5,35,48,56,58] interval = 5 inv = (x[0] + x[1])/interval I will like to split y2 into inv parts so my answer should be: [58 57.85 57.7 57.55 57.4 57.25 57.1 56.95 56.8 56.65 56.5 56.35 56.2 56.05 55.9 55.75 55.6 55.45 55.3 55.15 55...…….49...…………..12...….6 ………...5...……..] I will like to mention that inv will always be (x[0] + x[1])

问题 Hi I am trying to split the values in a (y2) list into (inv) amount of parts. x = [0,100,200,300,400,500,600,700,800,900,1000,1100] y2 = [58,55,49,12,6,5,4,4.5,35,48,56,58] interval = 5 inv = (x[0] + x[1])/interval I will like to split y2 into inv parts so my answer should be: [58 57.85 57.7 57.55 57.4 57.25 57.1 56.95 56.8 56.65 56.5 56.35 56.2 56.05 55.9 55.75 55.6 55.45 55.3 55.15 55...…….49...…………..12...….6 ………...5...……..] I will like to mention that inv will always be (x[0] + x[1])

问题 I'm having trouble with a Python Teradata (tdodbc) query with looping through the same query with different variables and merging the results. I received good direction in another post and ended up here. My issue now is that the dataframe only ends up with query results of the final variable in the loop, "state5". Unfortunately we have 5 states each in their own databases with the same schema. I can run the same query, but want to loop the variables so I can run for all 5 states and return an

问题 I'm having trouble with a Python Teradata (tdodbc) query with looping through the same query with different variables and merging the results. I received good direction in another post and ended up here. My issue now is that the dataframe only ends up with query results of the final variable in the loop, "state5". Unfortunately we have 5 states each in their own databases with the same schema. I can run the same query, but want to loop the variables so I can run for all 5 states and return an

问题 On Hackerrank I came across this problem. I have a function that takes in 3 arguments. Example --> function shiftStrings("string", leftShifts, rightShifts); LeftShifts and rightShifts being integers. Left Shift: A single circular rotation of the string in which the first character becomes the last character and all other characters are shifted one index to the left. For example, abcde becomes bcdea after one left shift and cdeab after two left shifts. Right Shift: A single circular rotation

问题 On Hackerrank I came across this problem. I have a function that takes in 3 arguments. Example --> function shiftStrings("string", leftShifts, rightShifts); LeftShifts and rightShifts being integers. Left Shift: A single circular rotation of the string in which the first character becomes the last character and all other characters are shifted one index to the left. For example, abcde becomes bcdea after one left shift and cdeab after two left shifts. Right Shift: A single circular rotation

问题 If iteratively writing to a file in a nested for loop, is there any difference in efficiency to open the file before the loop and close it after, rather than open and close within? See the following: int main(){ FILE *file1; char filename; int i, j, N, M; for(i=0; i<N; i++){ file1=fopen(filename, "a"); for(j=0; j<M; j++){ fprintf(file1,"%d %d\n", i, j); } fclose(file1); } return 1; } or int main(){ FILE *file1; char filename; int i, j, N, M; file1=fopen(filename, "a"); for(i=0; i<N; i++){ for

问题 I want to read several files json files and write them to a dataframe with a for-loop. review_categories = ["beauty", "pet"] for i in review_categories: filename = "D:\\Library\\reviews_{}.json".format(i) output = pd.read_json(path_or_buf=filename, lines=True) return output The problem is I want each review category to have its own variable, like a dataframe called "beauty_reviews", and another called "pet_reviews", containing the data read from reviews_beauty.json and reviews_pet.json