character

问题 I need to figure out which character was typed into a text field from within the handler that is called by jQuery's keydown function. key.which gives me only the keycode, but I need to figure out which ASCII character key represents. How do I do this? 回答1: For character input, it is suggested you use keypress() , which will report the actual ASCII code for the character pressed. It automatically takes care of letter case, and ignores non-character presses. In either case, you can use

问题 Consider the string: string str="A C# string"; What would be most efficient way to printout the ASCII value of each character in str using C#. 回答1: Here's an alternative since you don't like the cast to int: foreach(byte b in System.Text.Encoding.UTF8.GetBytes(str.ToCharArray())) Console.Write(b.ToString()); 回答2: Just cast each character to an int: for (int i = 0; i < str.length; i++) Console.Write(((int)str[i]).ToString()); 回答3: This example might help you. by using simple casting you can

问题 I have an NSString or NSMutableString and would like to get the number of occurrences of a particular character. I need to do this for quite a few characters -- uppercase English characters in this case -- so it would be nice for it to be quick. 回答1: replaceOccurrencesOfString:withString:options:range: will return the number of characters replaced in a NSMutableString . [string replaceOccurrencesOfString:@"A" withString:@"B" options:NSLiteralSearch range:NSMakeRange(0, [receiver length])];

问题 I need to delete the first 3 letters of a string and the last 3 letters of a string. I know I can use substr() to start at a certain character but if I need to strip both first and last characters i'm not sure if I can actually use this. Any suggestions? 回答1: Pass a negative value as the length argument (the 3rd argument) to substr(), like: $result = substr($string, 3, -3); So this: <?php $string = "Sean Bright"; $string = substr($string, 3, -3); echo $string; ?> Outputs: n Bri 回答2: Use

问题 I would like to change the format (class) of some columns of my data.frame object ( mydf ) from charactor to factor . I don't want to do this when I'm reading the text file by read.table() function. Any help would be appreciated. 回答1: Hi welcome to the world of R. mtcars #look at this built in data set str(mtcars) #allows you to see the classes of the variables (all numeric) #one approach it to index with the $ sign and the as.factor function mtcars$am <- as.factor(mtcars$am) #another

问题 I would like to change the format (class) of some columns of my data.frame object ( mydf ) from charactor to factor . I don't want to do this when I'm reading the text file by read.table() function. Any help would be appreciated. 回答1: Hi welcome to the world of R. mtcars #look at this built in data set str(mtcars) #allows you to see the classes of the variables (all numeric) #one approach it to index with the $ sign and the as.factor function mtcars$am <- as.factor(mtcars$am) #another

问题 I want the user to input a maximum of 8 numbers as it is a field for Mobile number. This is my JTextField. txtMobile = new JTextField(); txtMobile.setColumns(10); txtMobile.setBounds(235, 345, 145, 25); add(txtMobile); While we're at it, how do I check for invalid characters like >> '^%$* in a JTextField ? 1)Maximum Length 2)Accepts only numbers 3)Check for invalid characters 4)Check if it's a valid email address Please help :D 回答1: You could use a JFormattedField , check out How to Use

问题 I try to find and move all files with the character "{" (without the quotes) for example filename{{xyz}}.txt My Code: @echo OFF setlocal enableextensions disabledelayedexpansion set "source=C:\Users\OLD\*.txt" set "target=C:\Users\NEW" set "searchString=}" set "found=" for /f "delims=" %%a in (' findstr /m /i /l /c:"%searchString%" "%source%" 2^>nul ') do ( if not defined found set "found=1" move "%%a" "%target%" ) if not defined found ( echo not found ) This script found all characters,

问题 I used following code snippet to replace text private void textBox1_TextChanged(object sender, EventArgs e) { string A = textBox1.Text.Trim(); string B = textBox1.Text.Trim(); A = A.Replace("AB", "CD"); A = A.Replace("GF", "HI"); A = A.Replace("AC", "QW"); A = A.Replace("VB", "GG"); textBox2.Text = (A); } but i wants to ignore this replace technique within || these symbol.As a example my code do this when i type AB GF in a txtbox1,txtbox2 replace as following CD HI. Now i need when i type |AB

问题 I'm working with dplyr and created code to compute new data that is plotted with ggplot. I want to create a function with this code. It should take a name of a column of the data frame that is manipulated by dplyr. However, trying to work with columnnames does not work. Please consider the minimal example below: df <- data.frame(A = seq(-5, 5, 1), B = seq(0,10,1)) library(dplyr) foo <- function (x) { df %>% filter(x < 1) } foo(B) Error in filter_impl(.data, dots(...), environment()) : object