concatenation

问题 I know that if I do print ("f" + 2 * "o") in python the output will be foo . But how do I do the same thing in a bash script? 回答1: You can use bash command substitution to be more portable across systems than to use a variant specific command. $ myString=$(printf "%10s");echo ${myString// /m} # echoes 'm' 10 times mmmmmmmmmm $ myString=$(printf "%10s");echo ${myString// /rep} # echoes 'rep' 10 times reprepreprepreprepreprepreprep Wrapping it up in a more usable shell-function repeatChar() {

问题 I'm wondering why this is so: Ruby concatenates two strings if there is a space between the plus and the next string. But if there is no space, does it apply some unary operator? params['controller'].to_s + '/' # => "posts/" params['controller'].to_s +'/' # => NoMethodError: undefined method `+@' for "/":String 回答1: The parser is interpreting +'/' as the first parameter to the to_s method call. It is treating these two statements as equivalent: > params['controller'].to_s +'/' # NoMethodError

问题 I'm wondering why this is so: Ruby concatenates two strings if there is a space between the plus and the next string. But if there is no space, does it apply some unary operator? params['controller'].to_s + '/' # => "posts/" params['controller'].to_s +'/' # => NoMethodError: undefined method `+@' for "/":String 回答1: The parser is interpreting +'/' as the first parameter to the to_s method call. It is treating these two statements as equivalent: > params['controller'].to_s +'/' # NoMethodError

问题 Before I get to my issue, I have searched around for an answer but cannot seem to find anything specific to my case. Ok, basically I call my script via cmd and pass in 16 args and use them to set some variables I have. I am creating a custom html report for our company use. These variables I just use to dynamically set the values I want where they are in html string. The error I get is: >>> python -u "htmltest.py" 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Traceback (most recent call last): File

问题 I'm building a string piece by piece in my program and am currently using a mix of strcat() when I'm adding a simple string onto the end, but when im adding a formatted string I'm using sprintf() e.g.: int one = 1; sprintf(instruction + strlen(instruction), " number %d", one); is it possible to concatenate formatted string using strcat() or what is the preferred method for this? 回答1: Your solution will work. Calling strlen is a bit awkward (particularly if the string gets quite long). sprintf

问题 What's the difference between concat, uglify, and minify tasks in grunt? I set up an uglify task for all of my site's javascript tasks, and it seemed to both minify and concatenate them. Grunt's site has a great description for how to configure each task, but it doesn't seem to explain what each task actually does. 回答1: Concatenation is just appending all of the static files into one large file . Minification is just removing unnecesary whitespace and redundant / optional tokens like curlys

问题 I have some trouble understanding what numpy's dstack function is actually doing. The documentation is rather sparse and just says: Stack arrays in sequence depth wise (along third axis). Takes a sequence of arrays and stack them along the third axis to make a single array. Rebuilds arrays divided by dsplit . This is a simple way to stack 2D arrays (images) into a single 3D array for processing. So either I am really stupid and the meaning of this is obvious or I seem to have some

问题 I am trying to get into some PHP and I can't seem to figure out the following. I can create a string by means of PHP with concatenation: echo 'This ' . 'string ' . 'was ' . 'made ' . 'with concatenation.' . "\n"; But what if you want to do this with a variable? (I am guessing WP's functions can be called variables.) I am quite lost here. The following does not work. Or at least, my text editor throws an unknown error. <?php if ( is_404() ) { echo "<script src='" . get_stylesheet_directory_uri

问题 I made a smaller scenario of my bigger problem. What I try to do is pass a string to a function which will make a new string out of it. However I ran into some problems. I have defined string as typedef char string[1024]; Then I have a function that takes a string and makes a new string which get filled with the old string and a dot char string* add_sth_to_string(char* msg){ string* newStr=malloc(sizeof(string)); // malloc a newStr strcpy(*newStr, msg); // copying msg to newStr char buff[1024

问题 I'm getting an error which i can't solve, even after about an hour of research. Conversion from String "Waseem-PC\Waseem" to long is not valid This error really gets annoying, I tried everything! I would really appreciate help from you. I would love to give your answers a thumbs up but i have to have a bigger rep. Here is my code Private Sub RichTextBox2_KeyPress(sender As Object, e As KeyPressEventArgs) Handles RichTextBox2.KeyPress If Asc(e.KeyChar) = Keys.Enter Then RichTextBox1.Text =