append

问题 This question already has answers here : List of lists changes reflected across sublists unexpectedly (13 answers) Closed 3 years ago . I'm getting mad with list indexes, and can't explain what I'm doing wrong. I have this piece of code in which I want to create a list of lists, each one containing values of the same circuit parameter (voltage, current etc..) that I'm reading from a csv file that looks like this: Sample, V1, I1, V2, I2 0, 3, 0.01, 3, 0.02 1, 3, 0.01, 3, 0.03 And so on. What I

问题 am trying to add a file to an existing archive using the following code. When run no errors or exceptions are shown but no files are added to the archive either. Any ideas why? using (FileStream fileStream = File.Open(archivePath, FileMode.Open, FileAccess.ReadWrite)) using (ZipOutputStream zipToWrite = new ZipOutputStream(fileStream)) { zipToWrite.SetLevel(9); using (FileStream newFileStream = File.OpenRead(sourceFiles[0])) { byte[] byteBuffer = new byte[newFileStream.Length - 1];

问题 I am opening the file in append mode. I need to replace lines 2,3, and 4 in the file, and later I need to add the new data at the end of the file. 回答1: I think this is the FAQ answer that I've reposted to Stackoverflow the most. The perlfaq5 has the answer to How do I change, delete, or insert a line in a file, or append to the beginning of a file?. Forget about the append mode stuff. That's just going to make your life harder. The basic idea of inserting, changing, or deleting a line from a

问题 I'm having issues appending data to a list which is already in a list format. I have a program which will export results objects during a simulation loop. The data itself is stored as a list of matrices. My idea is to store those lists in a list, and then save this list of lists as an R object for later analysis, however I'm having some issues achieving this correctly. I'll show what I've done with small abstract example just using values instead of the matrix data from my simulation: Say I

问题 I am not happy with the accepted answer to Append an object to a list in R in amortized constant time? > list1 <- list("foo", pi) > bar <- list("A", "B") How can I append new element bar to list1 ? Clearly, c() does not work, it flattens bar : > c(list1, bar) [[1]] [1] "foo" [[2]] [1] 3.141593 [[3]] [1] "A" [[4]] [1] "B" Assignment to index works: > list1[[length(list1)+1]] <- bar > list1 [[1]] [1] "foo" [[2]] [1] 3.141593 [[3]] [[3]][[1]] [1] "A" [[3]][[2]] [1] "B" What is the efficiency of

问题 I'm working through Udacity and Dave Evans introduced an exercise about list properties list1 = [1,2,3,4] list2 = [1,2,3,4] list1=list1+[6] print(list1) list2.append(6) print(list2) list1 = [1,2,3,4] list2 = [1,2,3,4] def proc(mylist): mylist = mylist + [6] def proc2(mylist): mylist.append(6) # Can you explain the results given by the four print statements below? Remove # the hashes # and run the code to check. print (list1) proc(list1) print (list1) print (list2) proc2(list2) print (list2)

问题 I'm curious about the difference setText() and append() are creating. I'm writing a very basic editor with line numbers. I have a TextView to hold line numbers on the left, paired with an EditText on the right to hold the data. Here's the XML: <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="top"> <TextView android:id="@+id/line

问题 A simple append function like this (in F#): let rec app s t = match s with | [] -> t | (x::ss) -> x :: (app ss t) will crash when s becomes big, since the function is not tail recursive. I noticed that F#'s standard append function does not crash with big lists, so it must be implemented differently. So I wondered: How does a tail recursive definition of append look like? I came up with something like this: let rec comb s t = match s with | [] -> t | (x::ss) -> comb ss (x::t) let app2 s t =

问题 I'm trying to append the contents of a file myfile.txt to the end of a second file myfile2.txt in c. I can copy the contents, but I can't find a way to append. Here's my code: FILE *pFile; FILE *pFile2; char buffer[256]; pFile=fopen("myfile.txt", "r"); pFile2=fopen("myfile2.txt", r+); if(pFile==NULL) { perror("Error opening file."); } else { while(!feof(pFile)) { if(fgets(buffer, 100, pFile) != NULL) { fseek(pFile2, -100, SEEK_END); fprintf(pFile2, buffer); } } fclose(pFile); fclose(pFile2);

问题 I am trying to column-bind dataframes and having issue with pandas concat , as ignore_index=True doesn't seem to work: df1 = pd.DataFrame({'A': ['A0', 'A1', 'A2', 'A3'], 'B': ['B0', 'B1', 'B2', 'B3'], 'D': ['D0', 'D1', 'D2', 'D3']}, index=[0, 2, 3,4]) df2 = pd.DataFrame({'A1': ['A4', 'A5', 'A6', 'A7'], 'C': ['C4', 'C5', 'C6', 'C7'], 'D2': ['D4', 'D5', 'D6', 'D7']}, index=[ 5, 6, 7,3]) df1 # A B D # 0 A0 B0 D0 # 2 A1 B1 D1 # 3 A2 B2 D2 # 4 A3 B3 D3 df2 # A1 C D2 # 5 A4 C4 D4 # 6 A5 C5 D5 # 7