for-loop

问题 I have a large number of photos that are contained in over 100 directories. These are all pre-installation photos. I would like to keep the existing directory structure but add a \pre and \post directory in any directory that contains a .jpg photo. I dont want a subdirectory created if a given directory only contains other directories but not files For testing , I have a single .jpg in c:\temp\one\two\three. I ran this command in c:\temp: FOR /R c:\temp %G IN (*.jpg) DO mkdir pre However, it

问题 As an image and code that I attached below, I have a set of transaction data and each row has its industry name. reproducible example data: structure(list(Date = c(1201, 1201, 1201, 1201, 1201, 1201, 1201, 1201, 1201, 1201), Sex = c("Male", "Male", "Female", "Male", "Male", "Female", "Male", "Female", "Male", "Male"), Age = c(10, 15, 20, 15, 40, 50, 20, 30, 50, 20), City = c("Pheonix", "Atlanta", "Las Vegas", "Las Vegas", "Denver", "Pheonix", "Atlanta", "Las Vegas", "Las Vegas", "Minneapolis"

问题 This question already has answers here : Modifying list while iterating [duplicate] (7 answers) Closed 6 years ago . Code: arr = [ i for i in xrange(10) ] for i in arr: if i in arr: print i arr.pop(0) print arr And the output: $ python2.7 ts.py 0 2 4 6 8 [5, 6, 7, 8, 9] Why is this the result? Shouldn't it be [] ? 回答1: Updating a Sequence while Iterating has some unexpected results, which is why it is never recommended. The following graphic depicts how the variable i changes every time you

问题 This question already has answers here : Modifying list while iterating [duplicate] (7 answers) Closed 6 years ago . Code: arr = [ i for i in xrange(10) ] for i in arr: if i in arr: print i arr.pop(0) print arr And the output: $ python2.7 ts.py 0 2 4 6 8 [5, 6, 7, 8, 9] Why is this the result? Shouldn't it be [] ? 回答1: Updating a Sequence while Iterating has some unexpected results, which is why it is never recommended. The following graphic depicts how the variable i changes every time you

问题 I wondered what the performance overhead is of using Enumerable.Range was against using a foreach loop. For example: var stringArray = Enumerable.Range(0, 4).Select(i => string.Empty).ToArray(); VS. var stringArray = new string[4]; for (int i = 0; i < formatted.Length; i++) { stringArray[i] = string.Empty; } I spotted these question: Why is Enumerable.Range faster than a direct yield loop? Enumerable.Range implementation Thoughts on foreach with Enumerable.Range vs traditional for loop But I

问题 I have data on all the NCAA basketball games that have occurred since 2003. I am trying to implement a for loop that will calculate the average of a number of stats for each time at a point in time. Here is my for loop: library(data.table) roll_season_team_stats <- NULL for (i in 0:max(stats_DT$DayNum)) { stats <- stats_DT[DayNum < i] roll_stats <- dcast(stats_DT, TeamID+Season~.,fun=mean,na.rm=T,value.var = c('FGM', 'FGA', 'FGM3', 'FGA3', 'FTM', 'FTA', 'OR', 'DR', 'TO')) roll_stats$DayNum <-

问题 Sorry for the inexperience, I'm a beginning coder in R For example: If I were to make a FOR loop by chance and I have a collection of integers 1 to 100 (1:100), what would be the proper format to ensure that would print the numbers that are divisible by another number. In this case, 5 being the number divisible. I hear that using modulo would help in this instance %% This is what I think I should have. For (x in 1:100) { x%%5 == y } print(y) 回答1: for (x in 1:100) { if (x%%5 == 0) { print(x) }

问题 I'm a newbie to Python. I'm writing a very simple piece of code to print the contents of a list using 'for' loop with .format() and I want the output as below, but I'm getting this error: names = ['David', 'Peter', 'Michael', 'John', 'Bob'] for i in names: print("{}.{}".format(i, names[i])) print("{}.{}".format(i,breakfastMenu[i])) TypeError: list indices must be integers or slices, not str Expected output I want: 1. David 2. Peter 3. Michael 4. John 5. Bob Can someone please help me to get

问题 I'm a newbie to Python. I'm writing a very simple piece of code to print the contents of a list using 'for' loop with .format() and I want the output as below, but I'm getting this error: names = ['David', 'Peter', 'Michael', 'John', 'Bob'] for i in names: print("{}.{}".format(i, names[i])) print("{}.{}".format(i,breakfastMenu[i])) TypeError: list indices must be integers or slices, not str Expected output I want: 1. David 2. Peter 3. Michael 4. John 5. Bob Can someone please help me to get

问题 I have just started learning javascript, and I've hit a bit of a roadblock whilst designing the logic behind a 10 pin bowling scorecard. I would be really grateful if someone could help me figure out how, instead of my messy code below for the totalScore function, I could use a for loop that will add all of the values together. The code that I have so far is as follows. Thank you in advance! function Game() { this.scorecard = [] }; Game.prototype.add = function(frame) { this.scorecard.push