append

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: Python append() vs. + operator on lists, why do these give different results? What is the actual difference between "+" and "append" for list manipulation in Python? 回答1: There are two major differences. The first is that + is closer in meaning to extend than to append : >>> a = [1, 2, 3] >>> a + 4 Traceback (most recent call last): File "<pyshell#13>", line 1, in <module> a + 4 TypeError: can only concatenate

问题 I have a list with ~ 500 model objects. The names of this objects are v1: existing.list <- vector("list", 3) v1 <- names(existing.list) <- c("A", "B", "C") I now get different dataset, which i need to model, too, and save in the same list. The objects in this new dataset are overlapping with the some of the objects in existing.list . Because it is very time-consuming, i do want to keep the old results. The names of this new dataset are v2: v2 <- c("B", "C", "D") I first want to remove the

问题 I cant append text to a text file, it only overwrites the previous text. My code: //using JFileChooser to select where to save file PrintStream outputStream = MyFrame.ShowSaveDialog(); if(outputStream!=null){ outputStream.append(input); outputStream.close(); } Edited: The ShowSaveDialog returns a PrintStream. Here is the code for that method: public static PrintStream ShowSaveDialog(){ JFileChooser chooser = new JFileChooser(); FileNameExtensionFilter filter = new FileNameExtensionFilter(

问题 I am a beginner and am trying to simply insert an R data frame from RStudio into an existing Excel sheet without losing previous data in that sheet or overwriting the whole file, eg. insert new data frame (15 rows, 4 columns) in file "Reporting.xlsx" in Sheet "August" from row 16, column 1, so that the previous info is not lost ? Thank you ! 回答1: Something like this: library(openxlsx) library(dplyr) # Get existing data and append new data dat = readWorkbook("Reporting.xlsx", sheet="August")

问题 I'm trying to use XSLT to append context-param as last sibling. There's no common parent element so the task is a little bit harder. I'd like to append following element: <context-param> <param-name>miku</param-name> <param-value>kawaii</param-value> </context-param> as the last context-param element (eg. all context-param elements must be next to each other, they can't be scattered anywhere in xml) in following xml: <web-app> <not_interesting_element1/> <not_interesting_element2/> <context

问题 I am using an XMLParser to parse some XML data, which uses an NSMutableString *resultString to store the tag characters. At every (- parser: didStarElement...) method I allocate and init the resultString-ivar. - (void)parser: (NSXMLParser *)parser didStartElement: (NSString *)elementName namespaceURI: (NSString *)namespaceURI qualifiedName: (NSString *)qName attributes: (NSDictionary *)attributeDict { // Alot of if-statements to sort subtags // /.../ resultString = [[NSMutableString alloc]

问题 If you're here by way of my Skrollr.js: Looping action that will happen all the time while user is scrolling window question, then you know basically what's going on. Skrollr, which is the plugin I'm using, cannot handle an infinite looping action. So the recommendation made by @Prinzhorn was to use the "modulus operator". And I tried that out, as you can see HERE. However, that posed another problem, as you can also see there, due to the fact that I need an event to occur (the animation)

问题 I would like to know if there is, in Java, a function that can prefix a defined String to the beginning of every String of an array of Strings. For example, my_function({"apple", "orange", "ant"}, "eat an ") would return {"eat an apple", "eat an orange", "eat an ant"} Currently, I coded this function, but I wonder if it already exists. 回答1: Nope. Since it should be about a three-line function, you're probably better of just sticking with the one you coded. Update With Java 8, the syntax is

问题 I try to create modular application, so each page have contains own html and javascript code. I supposed to load all code dynamically like: var s = document.createElement("script"); s.type = "text/javascript"; s.src='function oncl() { alert("click");}'; $(".selector").append(s); $( ".selector" ). append('<input type="button" onclick="ocl();" /> <form action="../test/test_upload4.php" method="POST" enctype="multipart/form-data" name="getnamefile"> <input type="file" id="uploadfile" name=