Programs & Examples On #Rename

For anything regarding renaming. Could be applicable to a wide range of subjects. Should be replaced by a more domain-specific tag if applicable.

Renaming branches remotely in Git

Adding to the answers already given, here is a version that first checks whether the new branch already exists (so you can safely use it in a script)

if git ls-remote --heads "$remote" \
    | cut -f2 \
    | sed 's:refs/heads/::' \
    | grep -q ^"$newname"$; then
    echo "Error: $newname already exists"
    exit 1
fi
git push "$oldname" "$remote/$oldname:refs/heads/$newname" ":$oldname"

(the check is from this answer)

How to rename a component in Angular CLI?

As the first answer indicated, currently there is no way to rename components so we're all just talking about work-arounds! This is what i do:

  1. Create the new component you liked.

    ng generate component newName

  2. Use Visual studio code editor or whatever other editor to then conveniently move code/pieces side by side!

  3. In Linux, use grep & sed (find & replace) to find/replaces references.

    grep -ir "oldname"

    cd your folder

    sed -i 's/oldName/newName/g' *

JavaScript: Object Rename Key

Most of the answers here fail to maintain JS Object key-value pairs order. If you have a form of object key-value pairs on the screen that you want to modify, for example, it is important to preserve the order of object entries.

The ES6 way of looping through the JS object and replacing key-value pair with the new pair with a modified key name would be something like:

let newWordsObject = {};

Object.keys(oldObject).forEach(key => {
  if (key === oldKey) {
    let newPair = { [newKey]: oldObject[oldKey] };
    newWordsObject = { ...newWordsObject, ...newPair }
  } else {
    newWordsObject = { ...newWordsObject, [key]: oldObject[key] }
  }
});

The solution preserves the order of entries by adding the new entry in the place of the old one.

Rename specific column(s) in pandas

How do I rename a specific column in pandas?

From v0.24+, to rename one (or more) columns at a time,

If you need to rename ALL columns at once,

  • DataFrame.set_axis() method with axis=1. Pass a list-like sequence. Options are available for in-place modification as well.

rename with axis=1

df = pd.DataFrame('x', columns=['y', 'gdp', 'cap'], index=range(5))
df

   y gdp cap
0  x   x   x
1  x   x   x
2  x   x   x
3  x   x   x
4  x   x   x

With 0.21+, you can now specify an axis parameter with rename:

df.rename({'gdp':'log(gdp)'}, axis=1)
# df.rename({'gdp':'log(gdp)'}, axis='columns')
    
   y log(gdp) cap
0  x        x   x
1  x        x   x
2  x        x   x
3  x        x   x
4  x        x   x

(Note that rename is not in-place by default, so you will need to assign the result back.)

This addition has been made to improve consistency with the rest of the API. The new axis argument is analogous to the columns parameter—they do the same thing.

df.rename(columns={'gdp': 'log(gdp)'})

   y log(gdp) cap
0  x        x   x
1  x        x   x
2  x        x   x
3  x        x   x
4  x        x   x

rename also accepts a callback that is called once for each column.

df.rename(lambda x: x[0], axis=1)
# df.rename(lambda x: x[0], axis='columns')

   y  g  c
0  x  x  x
1  x  x  x
2  x  x  x
3  x  x  x
4  x  x  x

For this specific scenario, you would want to use

df.rename(lambda x: 'log(gdp)' if x == 'gdp' else x, axis=1)

Index.str.replace

Similar to replace method of strings in python, pandas Index and Series (object dtype only) define a ("vectorized") str.replace method for string and regex-based replacement.

df.columns = df.columns.str.replace('gdp', 'log(gdp)')
df
 
   y log(gdp) cap
0  x        x   x
1  x        x   x
2  x        x   x
3  x        x   x
4  x        x   x

The advantage of this over the other methods is that str.replace supports regex (enabled by default). See the docs for more information.


Passing a list to set_axis with axis=1

Call set_axis with a list of header(s). The list must be equal in length to the columns/index size. set_axis mutates the original DataFrame by default, but you can specify inplace=False to return a modified copy.

df.set_axis(['cap', 'log(gdp)', 'y'], axis=1, inplace=False)
# df.set_axis(['cap', 'log(gdp)', 'y'], axis='columns', inplace=False)

  cap log(gdp)  y
0   x        x  x
1   x        x  x
2   x        x  x
3   x        x  x
4   x        x  x

Note: In future releases, inplace will default to True.

Method Chaining
Why choose set_axis when we already have an efficient way of assigning columns with df.columns = ...? As shown by Ted Petrou in this answer set_axis is useful when trying to chain methods.

Compare

# new for pandas 0.21+
df.some_method1()
  .some_method2()
  .set_axis()
  .some_method3()

Versus

# old way
df1 = df.some_method1()
        .some_method2()
df1.columns = columns
df1.some_method3()

The former is more natural and free flowing syntax.

rename the columns name after cbind the data

If you pass only vectors to cbind() it creates a matrix, not a dataframe. Read ?data.frame.

Batch Renaming of Files in a Directory

#  another regex version
#  usage example:
#  replacing an underscore in the filename with today's date
#  rename_files('..\\output', '(.*)(_)(.*\.CSV)', '\g<1>_20180402_\g<3>')
def rename_files(path, pattern, replacement):
    for filename in os.listdir(path):
        if re.search(pattern, filename):
            new_filename = re.sub(pattern, replacement, filename)
            new_fullname = os.path.join(path, new_filename)
            old_fullname = os.path.join(path, filename)
            os.rename(old_fullname, new_fullname)
            print('Renamed: ' + old_fullname + ' to ' + new_fullname

Renaming a directory in C#

There is no difference between moving and renaming; you should simply call Directory.Move.

In general, if you're only doing a single operation, you should use the static methods in the File and Directory classes instead of creating FileInfo and DirectoryInfo objects.

For more advice when working with files and directories, see here.

Rename multiple files in cmd

This works for your specific case:

ren file?.txt "file? 1.1.txt" 

Rename multiple columns by names

There are a few answers mentioning the functions dplyr::rename_with and rlang::set_names already. By they are separate. this answer illustrates the differences between the two and the use of functions and formulas to rename columns.

rename_with from the dplyr package can use either a function or a formula to rename a selection of columns given as the .cols argument. For example passing the function name toupper:

library(dplyr)
rename_with(head(iris), toupper, starts_with("Petal"))

Is equivalent to passing the formula ~ toupper(.x):

rename_with(head(iris), ~ toupper(.x), starts_with("Petal"))

When renaming all columns, you can also use set_names from the rlang package. To make a different example, let's use paste0 as a renaming function. pasteO takes 2 arguments, as a result there are different ways to pass the second argument depending on whether we use a function or a formula.

rlang::set_names(head(iris), paste0, "_hi")
rlang::set_names(head(iris), ~ paste0(.x, "_hi"))

The same can be achieved with rename_with by passing the data frame as first argument .data, the function as second argument .fn, all columns as third argument .cols=everything() and the function parameters as the fourth argument .... Alternatively you can place the second, third and fourth arguments in a formula given as the second argument.

rename_with(head(iris), paste0, everything(), "_hi")
rename_with(head(iris), ~ paste0(.x, "_hi"))

rename_with only works with data frames. set_names is more generic and can also perform vector renaming

rlang::set_names(1:4, c("a", "b", "c", "d"))

How do I quickly rename a MySQL database (change schema name)?

There is a reason you cannot do this. (despite all the attempted answers)

  • Basic answers will work in many cases, and in others cause data corruptions.
  • A strategy needs to be chosen based on heuristic analysis of your database.
  • That is the reason this feature was implemented, and then removed. [doc]

You'll need to dump all object types in that database, create the newly named one and then import the dump. If this is a live system you'll need to take it down. If you cannot, then you will need to setup replication from this database to the new one.

If you want to see the commands that could do this, @satishD has the details, which conveys some of the challenges around which you'll need to build a strategy that matches your target database.

Rename a file using Java

Yes, you can use File.renameTo(). But remember to have the correct path while renaming it to a new file.

import java.util.Arrays;
import java.util.List;

public class FileRenameUtility {
public static void main(String[] a) {
    System.out.println("FileRenameUtility");
    FileRenameUtility renameUtility = new FileRenameUtility();
    renameUtility.fileRename("c:/Temp");
}

private void fileRename(String folder){
    File file = new File(folder);
    System.out.println("Reading this "+file.toString());
    if(file.isDirectory()){
        File[] files = file.listFiles();
        List<File> filelist = Arrays.asList(files);
        filelist.forEach(f->{
           if(!f.isDirectory() && f.getName().startsWith("Old")){
               System.out.println(f.getAbsolutePath());
               String newName = f.getAbsolutePath().replace("Old","New");
               boolean isRenamed = f.renameTo(new File(newName));
               if(isRenamed)
                   System.out.println(String.format("Renamed this file %s to  %s",f.getName(),newName));
               else
                   System.out.println(String.format("%s file is not renamed to %s",f.getName(),newName));
           }
        });

    }
}

}

Changing capitalization of filenames in Git

Sometimes you want to change the capitalization of a lot of file names on a case insensitive filesystem (e.g. on OS X or Windows). Doing git mv commands will tire quickly. To make things a bit easier this is what I do:

  1. Move all files outside of the directory to, let’s, say the desktop.
  2. Do a git add . -A to remove all files.
  3. Rename all files on the desktop to the proper capitalization.
  4. Move all the files back to the original directory.
  5. Do a git add .. Git should see that the files are renamed.

Now you can make a commit saying you have changed the file name capitalization.

windows batch file rename

Use REN Command

Ren is for rename

ren ( where the file is located ) ( the new name )

example

ren C:\Users\&username%\Desktop\aaa.txt bbb.txt

it will change aaa.txt to bbb.txt

Your code will be :

ren (file located)AAA_a001.jpg a001.AAA.jpg

ren (file located)BBB_a002.jpg a002.BBB.jpg

ren (file located)CCC_a003.jpg a003.CCC.jpg

and so on

IT WILL NOT WORK IF THERE IS SPACES!

Hope it helps :D

Re-order columns of table in Oracle

Since the release of Oracle 12c it is now easier to rearrange columns logically.

Oracle 12c added support for making columns invisible and that feature can be used to rearrange columns logically.

Quote from the documentation on invisible columns:

When you make an invisible column visible, the column is included in the table's column order as the last column.

Example

Create a table:

CREATE TABLE t (
    a INT,
    b INT,
    d INT,
    e INT
);

Add a column:

ALTER TABLE t ADD (c INT);

Move the column to the middle:

ALTER TABLE t MODIFY (d INVISIBLE, e INVISIBLE);
ALTER TABLE t MODIFY (d VISIBLE, e VISIBLE);

DESCRIBE t;

Name
----
A
B
C
D
E

Credits

I learned about this from an article by Tom Kyte on new features in Oracle 12c.

Is it possible to move/rename files in Git and maintain their history?

I make moving the files and then do

git add -A

which put in the sataging area all deleted/new files. Here git realizes that the file is moved.

git commit -m "my message"
git push

I do not know why but this works for me.

How do I rename a column in a database table using SQL?

Specifically for SQL Server, use sp_rename

USE AdventureWorks;
GO
EXEC sp_rename 'Sales.SalesTerritory.TerritoryID', 'TerrID', 'COLUMN';
GO

Rename a file in C#

Use:

public static class FileInfoExtensions
{
    /// <summary>
    /// Behavior when a new filename exists.
    /// </summary>
    public enum FileExistBehavior
    {
        /// <summary>
        /// None: throw IOException "The destination file already exists."
        /// </summary>
        None = 0,
        /// <summary>
        /// Replace: replace the file in the destination.
        /// </summary>
        Replace = 1,
        /// <summary>
        /// Skip: skip this file.
        /// </summary>
        Skip = 2,
        /// <summary>
        /// Rename: rename the file (like a window behavior)
        /// </summary>
        Rename = 3
    }


    /// <summary>
    /// Rename the file.
    /// </summary>
    /// <param name="fileInfo">the target file.</param>
    /// <param name="newFileName">new filename with extension.</param>
    /// <param name="fileExistBehavior">behavior when new filename is exist.</param>
    public static void Rename(this System.IO.FileInfo fileInfo, string newFileName, FileExistBehavior fileExistBehavior = FileExistBehavior.None)
    {
        string newFileNameWithoutExtension = System.IO.Path.GetFileNameWithoutExtension(newFileName);
        string newFileNameExtension = System.IO.Path.GetExtension(newFileName);
        string newFilePath = System.IO.Path.Combine(fileInfo.Directory.FullName, newFileName);

        if (System.IO.File.Exists(newFilePath))
        {
            switch (fileExistBehavior)
            {
                case FileExistBehavior.None:
                    throw new System.IO.IOException("The destination file already exists.");

                case FileExistBehavior.Replace:
                    System.IO.File.Delete(newFilePath);
                    break;

                case FileExistBehavior.Rename:
                    int dupplicate_count = 0;
                    string newFileNameWithDupplicateIndex;
                    string newFilePathWithDupplicateIndex;
                    do
                    {
                        dupplicate_count++;
                        newFileNameWithDupplicateIndex = newFileNameWithoutExtension + " (" + dupplicate_count + ")" + newFileNameExtension;
                        newFilePathWithDupplicateIndex = System.IO.Path.Combine(fileInfo.Directory.FullName, newFileNameWithDupplicateIndex);
                    }
                    while (System.IO.File.Exists(newFilePathWithDupplicateIndex));

                    newFilePath = newFilePathWithDupplicateIndex;
                    break;

                case FileExistBehavior.Skip:
                    return;
            }
        }
        System.IO.File.Move(fileInfo.FullName, newFilePath);
    }
}

How to use this code

class Program
{
    static void Main(string[] args)
    {
        string targetFile = System.IO.Path.Combine(@"D://test", "New Text Document.txt");
        string newFileName = "Foo.txt";

        // Full pattern
        System.IO.FileInfo fileInfo = new System.IO.FileInfo(targetFile);
        fileInfo.Rename(newFileName);

        // Or short form
        new System.IO.FileInfo(targetFile).Rename(newFileName);
    }
}

How to rename with prefix/suffix?

You can achieve a unix compatible multiple file rename (using wildcards) by creating a for loop:

for file in *; do
  mv $file new.${file%%}
done

How do I rename both a Git local and remote branch name?

If you have named a branch incorrectly AND pushed this to the remote repository follow these steps to rename that branch (based on this article):

  1. Rename your local branch:

    • If you are on the branch you want to rename:
      git branch -m new-name

    • If you are on a different branch:
      git branch -m old-name new-name

  2. Delete the old-name remote branch and push the new-name local branch:
    git push origin :old-name new-name

  3. Reset the upstream branch for the new-name local branch:
    Switch to the branch and then:
    git push origin -u new-name

How do I create batch file to rename large number of files in a folder?

@echo off
SETLOCAL ENABLEDELAYEDEXPANSION
SET old=Vacation2010
SET new=December
for /f "tokens=*" %%f in ('dir /b *.jpg') do (
  SET newname=%%f
  SET newname=!newname:%old%=%new%!
  move "%%f" "!newname!"
)

What this does is it loops over all .jpg files in the folder where the batch file is located and replaces the Vacation2010 with December inside the filenames.

Changing column names of a data frame

The error is caused by the "smart-quotes" (or whatever they're called). The lesson here is, "don't write your code in an 'editor' that converts quotes to smart-quotes".

names(newprice)[1]<-paste(“premium”)  # error
names(newprice)[1]<-paste("premium")  # works

Also, you don't need paste("premium") (the call to paste is redundant) and it's a good idea to put spaces around <- to avoid confusion (e.g. x <- -10; if(x<-3) "hi" else "bye"; x).

Renaming columns in Pandas

You could use str.slice for that:

df.columns = df.columns.str.slice(1)

In a Git repository, how to properly rename a directory?

1. Change a folder's name from oldfolder to newfolder

git mv oldfolder newfolder

2. If newfolder is already in your repository & you'd like to override it and use:- force

git mv -f oldfolder newfolder

Don't forget to add the changes to index & commit them after renaming with git mv.

3. Renaming foldername to folderName on case insensitive file systems

Simple renaming with a normal mv command(not git mv) won’t get recognized as a filechange from git. If you try it with the ‘git mv’ command like in the following line

git mv foldername folderName

If you’re using a case insensitive filesystem, e.g. you’re on a Mac and you didn’t configure it to be case sensitive, you’ll experience an error message like this one:

fatal: renaming ‘foldername’ failed: Invalid argument

And here is what you can do in order to make it work:-

git mv foldername tempname && git mv tempname folderName

This splits up the renaming process by renaming the folder at first to a completely different foldername. After renaming it to the different foldername the folder can finally be renamed to the new folderName. After those ‘git mv’s, again, do not forget to add and commit the changes. Though this is probably not a beautiful technique, it works perfectly fine. The filesystem will still not recognize a change of the letter cases, but git does due to renaming it to a new foldername, and that’s all we wanted :)

How to rename a table in SQL Server?

Nothing worked from proposed here .. So just pored the data into new table

SELECT * 
INTO [acecodetable].['PSCLineReason']
FROM [acecodetable].['15_PSCLineReason'];

maybe will be useful for someone..

In my case it didn't recognize the new schema also the dbo was the owner..

UPDATE

EXECUTE sp_rename N'[acecodetable].[''TradeAgreementClaim'']', N'TradeAgreementClaim';

Worked for me. I found it from the script generated automatically when updating the PK for one of the tables. This way it recognized the new schema as well..

Gradle - Move a folder from ABC to XYZ

Your task declaration is incorrectly combining the Copy task type and project.copy method, resulting in a task that has nothing to copy and thus never runs. Besides, Copy isn't the right choice for renaming a directory. There is no Gradle API for renaming, but a bit of Groovy code (leveraging Java's File API) will do. Assuming Project1 is the project directory:

task renABCToXYZ {     doLast {         file("ABC").renameTo(file("XYZ"))     } } 

Looking at the bigger picture, it's probably better to add the renaming logic (i.e. the doLast task action) to the task that produces ABC.

How do I rename a MySQL schema?

If you're on the Model Overview page you get a tab with the schema. If you rightclick on that tab you get an option to "edit schema". From there you can rename the schema by adding a new name, then click outside the field. This goes for MySQL Workbench 5.2.30 CE

Edit: On the model overview it's under Physical Schemata

Screenshot:

enter image description here

Renaming files in a folder to sequential numbers

ls -1tr | rename -vn 's/.*/our $i;if(!$i){$i=1;} sprintf("%04d.jpg", $i++)/e'

rename -vn - remove n for off test mode

{$i=1;} - control start number

"%04d.jpg" - control count zero 04 and set output extension .jpg

How do I rename all folders and files to lowercase on Linux?

I needed to do this on a Cygwin setup on Windows 7 and found that I got syntax errors with the suggestions from above that I tried (though I may have missed a working option). However, this solution straight from Ubuntu forums worked out of the can :-)

ls | while read upName; do loName=`echo "${upName}" | tr '[:upper:]' '[:lower:]'`; mv "$upName" "$loName"; done

(NB: I had previously replaced whitespace with underscores using:

for f in *\ *; do mv "$f" "${f// /_}"; done

)

Replacement for "rename" in dplyr

dplyr >= 1.0.0

In addition to dplyr::rename in newer versions of dplyr is rename_with()

rename_with() renames columns using a function.

You can apply a function over a tidy-select set of columns using the .cols argument:

iris %>% 
  dplyr::rename_with(.fn = ~ gsub("^S", "s", .), .cols = where(is.numeric))

    sepal.Length sepal.Width Petal.Length Petal.Width    Species
1            5.1         3.5          1.4         0.2     setosa
2            4.9         3.0          1.4         0.2     setosa
3            4.7         3.2          1.3         0.2     setosa
4            4.6         3.1          1.5         0.2     setosa
5            5.0         3.6          1.4         0.2     setosa

How do I completely rename an Xcode project (i.e. inclusive of folders)?

XCode 11.0+.

It's really simple now. Just go to Project Navigator left panel of the XCode window.
Press Enter to make it active for rename, just like you change the folder name.
enter image description here

Just change the new name here, and XCode will ask you for renaming other pieces of stuff.

enter image description here.

Tap on Rename here and you are done.
If you are confused about your root folder name that why it's not changed, well it's just a folder. just renamed it with a new name.
enter image description here

Append date to filename in linux

I use this script in bash:

#!/bin/bash

now=$(date +"%b%d-%Y-%H%M%S")
FILE="$1"
name="${FILE%.*}"
ext="${FILE##*.}"

cp -v $FILE $name-$now.$ext

This script copies filename.ext to filename-date.ext, there is another that moves filename.ext to filename-date.ext, you can download them from here. Hope you find them useful!!

Renaming files using node.js

You'll need to use fs for that: http://nodejs.org/api/fs.html

And in particular the fs.rename() function:

var fs = require('fs');
fs.rename('/path/to/Afghanistan.png', '/path/to/AF.png', function(err) {
    if ( err ) console.log('ERROR: ' + err);
});

Put that in a loop over your freshly-read JSON object's keys and values, and you've got a batch renaming script.

fs.readFile('/path/to/countries.json', function(error, data) {
    if (error) {
        console.log(error);
        return;
    }

    var obj = JSON.parse(data);
    for(var p in obj) {
        fs.rename('/path/to/' + obj[p] + '.png', '/path/to/' + p + '.png', function(err) {
            if ( err ) console.log('ERROR: ' + err);
        });
    }
});

(This assumes here that your .json file is trustworthy and that it's safe to use its keys and values directly in filenames. If that's not the case, be sure to escape those properly!)

Rename multiple files based on pattern in Unix

My version of renaming mass files:

for i in *; do
    echo "mv $i $i"
done |
sed -e "s#from_pattern#to_pattern#g” > result1.sh
sh result1.sh

Changing file extension in Python

Using pathlib and preserving full path:

from pathlib import Path
p = Path('/User/my/path')
new_p = Path(p.parent.as_posix() + '/' + p.stem + '.aln')

Rails: How can I rename a database column in a Ruby on Rails migration?

Generate a Ruby on Rails migration:

$:> rails g migration Fixcolumnname

Insert code in the migration file (XXXXXfixcolumnname.rb):

class Fixcolumnname < ActiveRecord::Migration
  def change
    rename_column :table_name, :old_column, :new_column
  end
end

How do I rename the extension for a bunch of files?

This question explicitly mentions Bash, but if you happen to have ZSH available it is pretty simple:

zmv '(*).*' '$1.txt'

If you get zsh: command not found: zmv then simply run:

autoload -U zmv

And then try again.

Thanks to this original article for the tip about zmv.

Rename all files in a folder with a prefix in a single command

With rnm (you will need to install it):

rnm -ns 'Unix_/fn/' *

Or

rnm -rs '/^/Unix_/' *

P.S : I am the author of this tool.

Rename MySQL database

If your DB contains only MyISAM tables (do not use this method if you have InnoDB tables):

  1. shut down the MySQL server
  2. go to the mysql data directory and rename the database directory (Note: non-alpha characters need to be encoded in a special way)
  3. restart the server
  4. adjust privileges if needed (grant access to the new DB name)

You can script it all in one command so that downtime is just a second or two.

Renaming Column Names in Pandas Groupby function

The current (as of version 0.20) method for changing column names after a groupby operation is to chain the rename method. See this deprecation note in the documentation for more detail.

Deprecated Answer as of pandas version 0.20

This is the first result in google and although the top answer works it does not really answer the question. There is a better answer here and a long discussion on github about the full functionality of passing dictionaries to the agg method.

These answers unfortunately do not exist in the documentation but the general format for grouping, aggregating and then renaming columns uses a dictionary of dictionaries. The keys to the outer dictionary are column names that are to be aggregated. The inner dictionaries have keys that the new column names with values as the aggregating function.

Before we get there, let's create a four column DataFrame.

df = pd.DataFrame({'A' : list('wwwwxxxx'), 
                   'B':list('yyzzyyzz'), 
                   'C':np.random.rand(8), 
                   'D':np.random.rand(8)})

   A  B         C         D
0  w  y  0.643784  0.828486
1  w  y  0.308682  0.994078
2  w  z  0.518000  0.725663
3  w  z  0.486656  0.259547
4  x  y  0.089913  0.238452
5  x  y  0.688177  0.753107
6  x  z  0.955035  0.462677
7  x  z  0.892066  0.368850

Let's say we want to group by columns A, B and aggregate column C with mean and median and aggregate column D with max. The following code would do this.

df.groupby(['A', 'B']).agg({'C':['mean', 'median'], 'D':'max'})

            D         C          
          max      mean    median
A B                              
w y  0.994078  0.476233  0.476233
  z  0.725663  0.502328  0.502328
x y  0.753107  0.389045  0.389045
  z  0.462677  0.923551  0.923551

This returns a DataFrame with a hierarchical index. The original question asked about renaming the columns in the same step. This is possible using a dictionary of dictionaries:

df.groupby(['A', 'B']).agg({'C':{'C_mean': 'mean', 'C_median': 'median'}, 
                            'D':{'D_max': 'max'}})

            D         C          
        D_max    C_mean  C_median
A B                              
w y  0.994078  0.476233  0.476233
  z  0.725663  0.502328  0.502328
x y  0.753107  0.389045  0.389045
  z  0.462677  0.923551  0.923551

This renames the columns all in one go but still leaves the hierarchical index which the top level can be dropped with df.columns = df.columns.droplevel(0).

Renaming a branch in GitHub

As mentioned, delete the old one on GitHub and re-push, though the commands used are a bit more verbose than necessary:

git push origin :name_of_the_old_branch_on_github
git push origin new_name_of_the_branch_that_is_local

Dissecting the commands a bit, the git push command is essentially:

git push <remote> <local_branch>:<remote_branch>

So doing a push with no local_branch specified essentially means "take nothing from my local repository, and make it the remote branch". I've always thought this to be completely kludgy, but it's the way it's done.

As of Git 1.7 there is an alternate syntax for deleting a remote branch:

git push origin --delete name_of_the_remote_branch

As mentioned by @void.pointer in the comments

Note that you can combine the 2 push operations:

git push origin :old_branch new_branch

This will both delete the old branch and push the new one.

This can be turned into a simple alias that takes the remote, original branch and new branch name as arguments, in ~/.gitconfig:

[alias]
    branchm = "!git branch -m $2 $3 && git push $1 :$2 $3 -u #"

Usage:

git branchm origin old_branch new_branch

Note that positional arguments in shell commands were problematic in older (pre 2.8?) versions of Git, so the alias might vary according to the Git version. See this discussion for details.

Convert row to column header for Pandas DataFrame,

In [21]: df = pd.DataFrame([(1,2,3), ('foo','bar','baz'), (4,5,6)])

In [22]: df
Out[22]: 
     0    1    2
0    1    2    3
1  foo  bar  baz
2    4    5    6

Set the column labels to equal the values in the 2nd row (index location 1):

In [23]: df.columns = df.iloc[1]

If the index has unique labels, you can drop the 2nd row using:

In [24]: df.drop(df.index[1])
Out[24]: 
1 foo bar baz
0   1   2   3
2   4   5   6

If the index is not unique, you could use:

In [133]: df.iloc[pd.RangeIndex(len(df)).drop(1)]
Out[133]: 
1 foo bar baz
0   1   2   3
2   4   5   6

Using df.drop(df.index[1]) removes all rows with the same label as the second row. Because non-unique indexes can lead to stumbling blocks (or potential bugs) like this, it's often better to take care that the index is unique (even though Pandas does not require it).

Renaming part of a filename

Something like this will do it. The for loop may need to be modified depending on which filenames you wish to capture.

for fspec1 in DET01-ABC-5_50-*.dat ; do
    fspec2=$(echo ${fspec1} | sed 's/-ABC-/-XYZ-/')
    mv ${fspec1} ${fspec2}
done

You should always test these scripts on copies of your data, by the way, and in totally different directories.

batch file - counting number of files in folder and storing in a variable

FOR /f "delims=" %%i IN ('attrib.exe ./*.* ^| find /v "File not found - " ^| find /c /v ""') DO SET myVar=%%i
ECHO %myVar%

This is based on the (much) earlier post that points out that the count would be wrong for an empty directory if you use DIR rather than attrib.exe.

For anyone else who got stuck on the syntax for putting the command in a FOR loop, enclose the command in single quotes (assuming it doesn't contain them) and escape pipes with ^.

How to capture UIView to UIImage without loss of quality on retina display

Some times drawRect Method makes problem so I got these answers more appropriate. You too may have a look on it Capture UIImage of UIView stuck in DrawRect method

How to get HTTP response code for a URL in Java?

This is the full static method, which you can adapt to set waiting time and error code when IOException happens:

  public static int getResponseCode(String address) {
    return getResponseCode(address, 404);
  }

  public static int getResponseCode(String address, int defaultValue) {
    try {
      //Logger.getLogger(WebOperations.class.getName()).info("Fetching response code at " + address);
      URL url = new URL(address);
      HttpURLConnection connection = (HttpURLConnection) url.openConnection();
      connection.setConnectTimeout(1000 * 5); //wait 5 seconds the most
      connection.setReadTimeout(1000 * 5);
      connection.setRequestProperty("User-Agent", "Your Robot Name");
      int responseCode = connection.getResponseCode();
      connection.disconnect();
      return responseCode;
    } catch (IOException ex) {
      Logger.getLogger(WebOperations.class.getName()).log(Level.INFO, "Exception at {0} {1}", new Object[]{address, ex.toString()});
      return defaultValue;
    }
  }

Converting Stream to String and back...what are we missing?

In usecase where you want to serialize/deserialize POCOs, Newtonsoft's JSON library is really good. I use it to persist POCOs within SQL Server as JSON strings in an nvarchar field. Caveat is that since its not true de/serialization, it will not preserve private/protected members and class hierarchy.

What is difference between Axios and Fetch?

Benefits of axios:

  • Transformers: allow performing transforms on data before request is made or after response is received
  • Interceptors: allow you to alter the request or response entirely (headers as well). also perform async operations before request is made or before Promise settles
  • Built-in XSRF protection

Advantages of axios over fetch

addEventListener, "change" and option selection

The problem is that you used the select option, this is where you went wrong. Select signifies that a textbox or textArea has a focus. What you need to do is use change. "Fires when a new choice is made in a select element", also used like blur when moving away from a textbox or textArea.

function start(){
      document.getElementById("activitySelector").addEventListener("change", addActivityItem, false);
      }

function addActivityItem(){
      //option is selected
      alert("yeah");
}

window.addEventListener("load", start, false);

Closing Twitter Bootstrap Modal From Angular Controller

You can do it like this:

angular.element('#modal').modal('hide');

Set mouse focus and move cursor to end of input using jQuery

    function focusCampo(id){
        var inputField = document.getElementById(id);
        if (inputField != null && inputField.value.length != 0){
            if (inputField.createTextRange){
                var FieldRange = inputField.createTextRange();
                FieldRange.moveStart('character',inputField.value.length);
                FieldRange.collapse();
                FieldRange.select();
            }else if (inputField.selectionStart || inputField.selectionStart == '0') {
                var elemLen = inputField.value.length;
                inputField.selectionStart = elemLen;
                inputField.selectionEnd = elemLen;
                inputField.focus();
            }
        }else{
            inputField.focus();
        }
    }

$('#urlCompany').focus(focusCampo('urlCompany'));

works for all ie browsers..

Retrieving the COM class factory for component failed

The CLSID you describe is for the Microsoft.Office.Interop.Excel.ApplicationClass. This class basically launches excel.exe through InprocServer32. If you don't have it installed then it will return the error message you received above.

Static linking vs dynamic linking

Dynamic linking requires extra time for the OS to find the dynamic library and load it. With static linking, everything is together and it is a one-shot load into memory.

Also, see DLL Hell. This is the scenario where the DLL that the OS loads is not the one that came with your application, or the version that your application expects.

How do I add a Maven dependency in Eclipse?

I have faced the similar issue and fixed by copying the missing Jar files in to .M2 Path,

For example: if you see the error message as Missing artifact tws:axis-client:jar:8.7 then you have to download "axis-client-8.7.jar" file and paste the same in to below location will resolve the issue.

C:\Users\UsernameXXX.m2\repository\tws\axis-client\8.7(Paste axis-client-8.7.jar).

finally, right click on project->Maven->Update Project...Thats it.

happy coding.

How to set viewport meta for iPhone that handles rotation properly?

just want to share, i've played around with the viewport settings for my responsive design, if i set the Max scale to 0.8, the initial scale to 1 and scalable to no then i get the smallest view in portrait mode and the iPad view for landscape :D... this is properly an ugly hack but it seems to work, i don't know why so i won't be using it, but interesting results

<meta name="viewport" content="user-scalable=no, initial-scale = 1.0,maximum-scale = 0.8,width=device-width" />

enjoy :)

What is dynamic programming?

Dynamic programming is when you use past knowledge to make solving a future problem easier.

A good example is solving the Fibonacci sequence for n=1,000,002.

This will be a very long process, but what if I give you the results for n=1,000,000 and n=1,000,001? Suddenly the problem just became more manageable.

Dynamic programming is used a lot in string problems, such as the string edit problem. You solve a subset(s) of the problem and then use that information to solve the more difficult original problem.

With dynamic programming, you store your results in some sort of table generally. When you need the answer to a problem, you reference the table and see if you already know what it is. If not, you use the data in your table to give yourself a stepping stone towards the answer.

The Cormen Algorithms book has a great chapter about dynamic programming. AND it's free on Google Books! Check it out here.

why I can't get value of label with jquery and javascript?

Label's aren't form elements. They don't have a value. They have innerHTML and textContent.

Thus,

$('#telefon').html() 
// or
$('#telefon').text()

or

var telefon = document.getElementById('telefon');
telefon.innerHTML;

If you are starting with your form element, check out the labels list of it. That is,

var el = $('#myformelement');
var label = $( el.prop('labels') );
// label.html();
// el.val();
// blah blah blah you get the idea

Initializing a list to a known number of elements in Python

@Steve already gave a good answer to your question:

verts = [None] * 1000

Warning: As @Joachim Wuttke pointed out, the list must be initialized with an immutable element. [[]] * 1000 does not work as expected because you will get a list of 1000 identical lists (similar to a list of 1000 points to the same list in C). Immutable objects like int, str or tuple will do fine.

Alternatives

Resizing lists is slow. The following results are not very surprising:

>>> N = 10**6

>>> %timeit a = [None] * N
100 loops, best of 3: 7.41 ms per loop

>>> %timeit a = [None for x in xrange(N)]
10 loops, best of 3: 30 ms per loop

>>> %timeit a = [None for x in range(N)]
10 loops, best of 3: 67.7 ms per loop

>>> a = []
>>> %timeit for x in xrange(N): a.append(None)
10 loops, best of 3: 85.6 ms per loop

But resizing is not very slow if you don't have very large lists. Instead of initializing the list with a single element (e.g. None) and a fixed length to avoid list resizing, you should consider using list comprehensions and directly fill the list with correct values. For example:

>>> %timeit a = [x**2 for x in xrange(N)]
10 loops, best of 3: 109 ms per loop

>>> def fill_list1():
    """Not too bad, but complicated code"""
    a = [None] * N
    for x in xrange(N):
        a[x] = x**2
>>> %timeit fill_list1()
10 loops, best of 3: 126 ms per loop

>>> def fill_list2():
    """This is slow, use only for small lists"""
    a = []
    for x in xrange(N):
        a.append(x**2)
>>> %timeit fill_list2()
10 loops, best of 3: 177 ms per loop

Comparison to numpy

For huge data set numpy or other optimized libraries are much faster:

from numpy import ndarray, zeros
%timeit empty((N,))
1000000 loops, best of 3: 788 ns per loop

%timeit zeros((N,))
100 loops, best of 3: 3.56 ms per loop

Capitalize the first letter of both words in a two word string

Match a regular expression that starts at the beginning ^ or after a space [[:space:]] and is followed by an alphabetical character [[:alpha:]]. Globally (the g in gsub) replace all such occurrences with the matched beginning or space and the upper-case version of the matched alphabetical character, \\1\\U\\2. This has to be done with perl-style regular expression matching.

gsub("(^|[[:space:]])([[:alpha:]])", "\\1\\U\\2", name, perl=TRUE)
# [1] "Zip Code"    "State"       "Final Count"

In a little more detail for the replacement argument to gsub(), \\1 says 'use the part of x matching the first sub-expression', i.e., the part of x matching (^|[[:spacde:]]). Likewise, \\2 says use the part of x matching the second sub-expression ([[:alpha:]]). The \\U is syntax enabled by using perl=TRUE, and means to make the next character Upper-case. So for "Zip code", \\1 is "Zip", \\2 is "code", \\U\\2 is "Code", and \\1\\U\\2 is "Zip Code".

The ?regexp page is helpful for understanding regular expressions, ?gsub for putting things together.

Installing Python library from WHL file

From How do I install a Python package with a .whl file? [sic], How do I install a Python package USING a .whl file ?

For all Windows platforms:

1) Download the .WHL package install file.

2) Make Sure path [C:\Progra~1\Python27\Scripts] is in the system PATH string. This is for using both [pip.exe] and [easy-install.exe].

3) Make sure the latest version of pip.EXE is now installed. At this time of posting:

pip.EXE --version

  pip 9.0.1 from C:\PROGRA~1\Python27\lib\site-packages (python 2.7)

4) Run pip.EXE in an Admin command shell.

 - Open an Admin privileged command shell.

 > easy_install.EXE --upgrade  pip

 - Check the pip.EXE version:
 > pip.EXE --version

 pip 9.0.1 from C:\PROGRA~1\Python27\lib\site-packages (python 2.7)

 > pip.EXE install --use-wheel --no-index 
     --find-links="X:\path to wheel file\DownloadedWheelFile.whl"

Be sure to double-quote paths or path\filenames with embedded spaces in them ! Alternatively, use the MSW 'short' paths and filenames.

Error: No default engine was specified and no extension was provided

If you wish to render a html file, use:

response.sendfile('index.html');

Then you remove:

app.set('view engine', 'html');

Put your *.html in the views directory, or serve a public directory as static dir and put the index.html in the public dir.

Simple Android grid example using RecyclerView with GridLayoutManager (like the old GridView)

Set in RecyclerView initialization

recyclerView.setLayoutManager(new GridLayoutManager(this, 4));

How do I check if a string contains another string in Objective-C?

Swift 4 And Above

let str = "Hello iam midhun"

if str.contains("iam") {
  //contains substring
}
else {
  //doesn't contain substring
}

Objective-C

NSString *stringData = @"Hello iam midhun";

if ([stringData containsString:@"iam"]) {
    //contains substring
}
else {
    //doesn't contain substring
}

iOS: Multi-line UILabel in Auto Layout

Expand your label set number of lines to 0 and also more importantly for auto layout set height to >= x. Auto layout will do the rest. You may also contain your other elements based on previous element to correctly position then.

auto layout

MyISAM versus InnoDB

I have briefly discussed this question in a table so you can conclude whether to go with InnoDB or MyISAM.

Here is a small overview of which db storage engine you should use in which situation:

                                                 MyISAM   InnoDB
----------------------------------------------------------------
Required full-text search                        Yes      5.6.4
----------------------------------------------------------------
Require transactions                                      Yes
----------------------------------------------------------------
Frequent select queries                          Yes      
----------------------------------------------------------------
Frequent insert, update, delete                           Yes
----------------------------------------------------------------
Row locking (multi processing on single table)            Yes
----------------------------------------------------------------
Relational base design                                    Yes

Summary

  • In almost all circumstances, InnoDB is the best way to go
  • But, frequent reading, almost no writing, use MyISAM
  • Full-text search in MySQL <= 5.5, use MyISAM

Cross compile Go on OSX?

Thanks to kind and patient help from golang-nuts, recipe is the following:

1) One needs to compile Go compiler for different target platforms and architectures. This is done from src folder in go installation. In my case Go installation is located in /usr/local/go thus to compile a compiler you need to issue make utility. Before doing this you need to know some caveats.

There is an issue about CGO library when cross compiling so it is needed to disable CGO library.

Compiling is done by changing location to source dir, since compiling has to be done in that folder

cd /usr/local/go/src

then compile the Go compiler:

sudo GOOS=windows GOARCH=386 CGO_ENABLED=0 ./make.bash --no-clean

You need to repeat this step for each OS and Architecture you wish to cross compile by changing the GOOS and GOARCH parameters.

If you are working in user mode as I do, sudo is needed because Go compiler is in the system dir. Otherwise you need to be logged in as super user. On Mac you may need to enable/configure SU access (it is not available by default), but if you have managed to install Go you possibly already have root access.

2) Once you have all cross compilers built, you can happily cross compile your application by using the following settings for example:

GOOS=windows GOARCH=386 go build -o appname.exe appname.go

GOOS=linux GOARCH=386 CGO_ENABLED=0 go build -o appname.linux appname.go

Change the GOOS and GOARCH to targets you wish to build.

If you encounter problems with CGO include CGO_ENABLED=0 in the command line. Also note that binaries for linux and mac have no extension so you may add extension for the sake of having different files. -o switch instructs Go to make output file similar to old compilers for c/c++ thus above used appname.linux can be any other extension.

Warning: mysqli_connect(): (HY000/1045): Access denied for user 'username'@'localhost' (using password: YES)

The same issue faced me with XAMPP 7 and opencart Arabic 3. Replacing localhost by the actual machine name reslove the issue.

Get Excel sheet name and use as variable in macro

in a Visual Basic Macro you would use

pName = ActiveWorkbook.Path      ' the path of the currently active file
wbName = ActiveWorkbook.Name     ' the file name of the currently active file
shtName = ActiveSheet.Name       ' the name of the currently selected worksheet

The first sheet in a workbook can be referenced by

ActiveWorkbook.Worksheets(1)

so after deleting the [Report] tab you would use

ActiveWorkbook.Worksheets("Report").Delete
shtName = ActiveWorkbook.Worksheets(1).Name

to "work on that sheet later on" you can create a range object like

Dim MySheet as Range
MySheet = ActiveWorkbook.Worksheets(shtName).[A1]

and continue working on MySheet(rowNum, colNum) etc. ...

shortcut creation of a range object without defining shtName:

Dim MySheet as Range
MySheet = ActiveWorkbook.Worksheets(1).[A1]

How to remove old Docker containers

Another method, which I got from Guillaume J. Charmes (credit where it is due):

docker rm `docker ps --no-trunc -aq`

will remove all containers in an elegant way.

And by Bartosz Bilicki, for Windows:

FOR /f "tokens=*" %i IN ('docker ps -a -q') DO docker rm %i

For PowerShell:

docker rm @(docker ps -aq)

An update with Docker 1.13 (Q4 2016), credit to VonC (later in this thread):

docker system prune will delete ALL unused data (i.e., in order: containers stopped, volumes without containers and images with no containers).

See PR 26108 and commit 86de7c0, which are introducing a few new commands to help facilitate visualizing how much space the Docker daemon data is taking on disk and allowing for easily cleaning up "unneeded" excess.

docker system prune

WARNING! This will remove:
    - all stopped containers
    - all volumes not used by at least one container
    - all images without at least one container associated to them
Are you sure you want to continue? [y/N] y

ExtJs Gridpanel store refresh

grid.store = store;
store.load({ params: { start: 0, limit: 20} });
grid.getView().refresh();

How to increase the timeout period of web service in asp.net?

you can do this in different ways:

  1. Setting a timeout in the web service caller from code (not 100% sure but I think I have seen this done);
  2. Setting a timeout in the constructor of the web service proxy in the web references;
  3. Setting a timeout in the server side, web.config of the web service application.

see here for more details on the second case:

http://msdn.microsoft.com/en-us/library/ff647786.aspx#scalenetchapt10_topic14

and here for details on the last case:

How to increase the timeout to a web service request?

Is there a way to remove unused imports and declarations from Angular 2+?

To be able to detect unused imports, code or variables, make sure you have this options in tsconfig.json file

"compilerOptions": {
    "noUnusedLocals": true,
    "noUnusedParameters": true
}

have the typescript compiler installed, ifnot install it with:

npm install -g typescript

and the tslint extension installed in Vcode, this worked for me, but after enabling I notice an increase amount of CPU usage, specially on big projects.

I would also recomend using typescript hero extension for organizing your imports.

Error: select command denied to user '<userid>'@'<ip-address>' for table '<table-name>'

For me, I accidentally included my local database name inside the SQL query, hence the access denied issue came up when I deployed.

I removed the database name from the SQL query and it got fixed.

single line comment in HTML

TL;DR For conforming browsers, yes; but there are no conforming browsers, so no.

According to the HTML 4 specification, <!------> hello--> is a perfectly valid comment. However, I've not found a browser which implements this correctly (i.e. per the specification) due to developers not knowing, nor following, the standards (as digitaldreamer pointed out).

You can find the definition of a comment for HTML4 on the w3c's website: http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4

Another thing that many browsers get wrong is that -- > closes a comment just like -->.

regular expression for DOT

You should use contains not matches

if(nom.contains("."))
    System.out.println("OK");
else
    System.out.println("Bad");

Addition for BigDecimal

It looks like from the Java docs here that add returns a new BigDecimal:

BigDecimal test = new BigDecimal(0);
System.out.println(test);
test = test.add(new BigDecimal(30));
System.out.println(test);
test = test.add(new BigDecimal(45));
System.out.println(test);

How to convert list of numpy arrays into single numpy array?

I checked some of the methods for speed performance and find that there is no difference! The only difference is that using some methods you must carefully check dimension.

Timing:

|------------|----------------|-------------------|
|            | shape (10000)  |  shape (1,10000)  |
|------------|----------------|-------------------|
| np.concat  |    0.18280     |      0.17960      |
|------------|----------------|-------------------|
|  np.stack  |    0.21501     |      0.16465      |
|------------|----------------|-------------------|
| np.vstack  |    0.21501     |      0.17181      |
|------------|----------------|-------------------|
|  np.array  |    0.21656     |      0.16833      |
|------------|----------------|-------------------|

As you can see I tried 2 experiments - using np.random.rand(10000) and np.random.rand(1, 10000) And if we use 2d arrays than np.stack and np.array create additional dimension - result.shape is (1,10000,10000) and (10000,1,10000) so they need additional actions to avoid this.

Code:

from time import perf_counter
from tqdm import tqdm_notebook
import numpy as np
l = []
for i in tqdm_notebook(range(10000)):
    new_np = np.random.rand(10000)
    l.append(new_np)



start = perf_counter()
stack = np.stack(l, axis=0 )
print(f'np.stack: {perf_counter() - start:.5f}')

start = perf_counter()
vstack = np.vstack(l)
print(f'np.vstack: {perf_counter() - start:.5f}')

start = perf_counter()
wrap = np.array(l)
print(f'np.array: {perf_counter() - start:.5f}')

start = perf_counter()
l = [el.reshape(1,-1) for el in l]
conc = np.concatenate(l, axis=0 )
print(f'np.concatenate: {perf_counter() - start:.5f}')

Taking screenshot on Emulator from Android Studio

1.First run your Application 2.Go to Tool-->Android-->Android Device Monitor Check image for more detail

Simulate Keypress With jQuery

You could try this SendKeys jQuery plugin:

http://bililite.com/blog/2011/01/23/improved-sendkeys/

$(element).sendkeys(string) inserts string at the insertion point in an input, textarea or other element with contenteditable=true. If the insertion point is not currently in the element, it remembers where the insertion point was when sendkeys was last called (if the insertion point was never in the element, it appends to the end).

How to use PHP to connect to sql server

Use localhost instead of your IP address.

e.g,

$myServer = "localhost";

And also double check your mysql username and password.

Filter Java Stream to 1 and only 1 element

The other answers that involve writing a custom Collector are probably more efficient (such as Louis Wasserman's, +1), but if you want brevity, I'd suggest the following:

List<User> result = users.stream()
    .filter(user -> user.getId() == 1)
    .limit(2)
    .collect(Collectors.toList());

Then verify the size of the result list.

if (result.size() != 1) {
  throw new IllegalStateException("Expected exactly one user but got " + result);
User user = result.get(0);
}

Paste a multi-line Java String in Eclipse

The EclipsePasteAsJavaString plug-in allows you to insert text as a Java string by Ctrl + Shift + V

Example

Paste as usual via Ctrl+V:

some text with tabs and new lines

Paste as Java string via Ctrl+Shift+V

"some text\twith tabs\r\n" + "and new \r\n" + "lines"

Array definition in XML?

Once I've seen such an interesting construction:

<Ids xmlns:id="http://schemas.microsoft.com/2003/10/Serialization/Arrays">
        <id:int>1787</id:int>
</Ids>

Hibernate: failed to lazily initialize a collection of role, no session or session was closed

I was experiencing the same issue so just added the @Transactional annotation from where I was calling the DAO method. It just works. I think the problem was Hibernate doesn't allow to retrieve sub-objects from the database unless specifically all the required objects at the time of calling.

IF EXIST C:\directory\ goto a else goto b problems windows XP batch files

@echo off

:START
rmdir temporary
cls
IF EXIST "temporary\." (echo The temporary directory exists) else echo The temporary directory doesn't exist
echo.
dir temporary /A:D
pause

echo.
echo.
echo Note the directory is not found
echo.
echo Press any key to make a temporary directory, cls, and test again
pause

Mkdir temporary
cls
IF EXIST "temporary\." (echo The temporary directory exists) else echo The temporary directory doesn't exist
echo.
dir temporary /A:D
pause
echo.
echo press any key to goto START and remove temporary directory 
pause 

goto START

How do I capture all of my compiler's output to a file?

The compiler warnings happen on stderr, not stdout, which is why you don't see them when you just redirect make somewhere else. Instead, try this if you're using Bash:

$ make &> results.txt

The & means "redirect stdout and stderr to this location". Other shells often have similar constructs.

Clearing my form inputs after submission

The easiest way would be to set the value of the form element. If you're using jQuery (which I would highly recommend) you can do this easily with

$('#element-id').val('')

For all input elements in the form this may work (i've never tried it)

$('#form-id').children('input').val('')

Note that .children will only find input elements one level down. If you need to find grandchildren or such .find() should work.

There may be a better way however this should work for you.

Vagrant stuck connection timeout retrying

My solution to this issue was that my old laptop was taking wayyyyyyyyyyy too long to start up. I opened Virtual Box, connected to the box and waited for the screen to load. Took about 8 minutes.

Then it connected and mounted my folders and went ahead.

just be patient sometimes!

How to set environment variable or system property in spring tests?

The right way to do this, starting with Spring 4.1, is to use a @TestPropertySource annotation.

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:whereever/context.xml")
@TestPropertySource(properties = {"myproperty = foo"})
public class TestWarSpringContext {
    ...    
}

See @TestPropertySource in the Spring docs and Javadocs.

What does the ^ (XOR) operator do?

XOR is a binary operation, it stands for "exclusive or", that is to say the resulting bit evaluates to one if only exactly one of the bits is set.

This is its function table:

a | b | a ^ b
--|---|------
0 | 0 | 0
0 | 1 | 1
1 | 0 | 1
1 | 1 | 0

This operation is performed between every two corresponding bits of a number.

Example: 7 ^ 10
In binary: 0111 ^ 1010

  0111
^ 1010
======
  1101 = 13

Properties: The operation is commutative, associative and self-inverse.

It is also the same as addition modulo 2.

BeanFactory vs ApplicationContext

do use BeanFactory for non-web applications because it supports only Singleton and Prototype bean-scopes.

While ApplicationContext container does support all the bean-scopes so you should use it for web applications.

Does JavaScript pass by reference?

Primitives are passed by value. But in case you only need to read the value of a primitve (and value is not known at the time when function is called) you can pass function which retrieves the value at the moment you need it.

function test(value) {
  console.log('retrieve value');
  console.log(value());
}

// call the function like this
var value = 1;
test(() => value);

How do I create a URL shortener?

This is my initial thoughts, and more thinking can be done, or some simulation can be made to see if it works well or any improvement is needed:

My answer is to remember the long URL in the database, and use the ID 0 to 9999999999999999 (or however large the number is needed).

But the ID 0 to 9999999999999999 can be an issue, because

  1. it can be shorter if we use hexadecimal, or even base62 or base64. (base64 just like YouTube using A-Z a-z 0-9 _ and -)
  2. if it increases from 0 to 9999999999999999 uniformly, then hackers can visit them in that order and know what URLs people are sending each other, so it can be a privacy issue

We can do this:

  1. have one server allocate 0 to 999 to one server, Server A, so now Server A has 1000 of such IDs. So if there are 20 or 200 servers constantly wanting new IDs, it doesn't have to keep asking for each new ID, but rather asking once for 1000 IDs
  2. for the ID 1, for example, reverse the bits. So 000...00000001 becomes 10000...000, so that when converted to base64, it will be non-uniformly increasing IDs each time.
  3. use XOR to flip the bits for the final IDs. For example, XOR with 0xD5AA96...2373 (like a secret key), and the some bits will be flipped. (whenever the secret key has the 1 bit on, it will flip the bit of the ID). This will make the IDs even harder to guess and appear more random

Following this scheme, the single server that allocates the IDs can form the IDs, and so can the 20 or 200 servers requesting the allocation of IDs. The allocating server has to use a lock / semaphore to prevent two requesting servers from getting the same batch (or if it is accepting one connection at a time, this already solves the problem). So we don't want the line (queue) to be too long for waiting to get an allocation. So that's why allocating 1000 or 10000 at a time can solve the issue.

pandas get column average/mean

you can use

df.describe() 

you will get basic statistics of the dataframe and to get mean of specific column you can use

df["columnname"].mean()

Jquery to get the id of selected value from dropdown

First set a custom attribute into your option for example nameid (you can set non-standardized attribute of an HTML element, it's allowed):

'<option nameid= "' + n.id + "' value="' + i + '">' + n.names + '</option>'

then you can easily get attribute value using jquery .attr() :

$('option:selected').attr("nameid")

For Example:

<select id="jobSel" class="longcombo" onchange="GetNameId">
    <option nameid="32" value="1">test1</option>
    <option nameid="67" value="1">test2</option>
    <option nameid="45" value="1">test3</option>    
    </select>    

Jquery:

function GetNameId(){
   alert($('#jobSel option:selected').attr("nameid"));
}

Paramiko's SSHClient with SFTP

paramiko.SFTPClient

Sample Usage:

import paramiko
paramiko.util.log_to_file("paramiko.log")

# Open a transport
host,port = "example.com",22
transport = paramiko.Transport((host,port))

# Auth    
username,password = "bar","foo"
transport.connect(None,username,password)

# Go!    
sftp = paramiko.SFTPClient.from_transport(transport)

# Download
filepath = "/etc/passwd"
localpath = "/home/remotepasswd"
sftp.get(filepath,localpath)

# Upload
filepath = "/home/foo.jpg"
localpath = "/home/pony.jpg"
sftp.put(localpath,filepath)

# Close
if sftp: sftp.close()
if transport: transport.close()

How to build and run Maven projects after importing into Eclipse IDE

When you add dependency in pom.xml , do a maven clean , and then maven build , it will add the jars into you project.

You can search dependency artifacts at http://mvnrepository.com/

And if it doesn't add jars it should give you errors which will mean that it is not able to fetch the jar, that could be due to broken repository or connection problems.

Well sometimes if it is one or two jars, better download them and add to build path , but with a lot of dependencies use maven.

Bootstrap 3 panel header with buttons wrong position

In this case you should add .clearfix at the end of container with floated elements.

<div class="panel-heading">
    <h4>Panel header</h4>
    <div class="btn-group pull-right">
        <a href="#" class="btn btn-default btn-sm">## Lock</a>
        <a href="#" class="btn btn-default btn-sm">## Delete</a>
        <a href="#" class="btn btn-default btn-sm">## Move</a>
    </div>
    <span class="clearfix"></span>
</div>

http://www.bootply.com/NCXkOtIkD6

XML Carriage return encoding

To insert a CR into XML, you need to use its character entity &#13;.

This is because compliant XML parsers must, before parsing, translate CRLF and any CR not followed by a LF to a single LF. This behavior is defined in the End-of-Line handling section of the XML 1.0 specification.

What's the right way to pass form element state to sibling/parent elements?

More recent answer with an example, which uses React.useState

Keeping the state in the parent component is the recommended way. The parent needs to have an access to it as it manages it across two children components. Moving it to the global state, like the one managed by Redux, is not recommended for same same reason why global variable is worse than local in general in software engineering.

When the state is in the parent component, the child can mutate it if the parent gives the child value and onChange handler in props (sometimes it is called value link or state link pattern). Here is how you would do it with hooks:


function Parent() {
    var [state, setState] = React.useState('initial input value');
    return <>
        <Child1 value={state} onChange={(v) => setState(v)} />
        <Child2 value={state}>
    </>
}

function Child1(props) {
    return <input
        value={props.value}
        onChange={e => props.onChange(e.target.value)}
    />
}

function Child2(props) {
    return <p>Content of the state {props.value}</p>
}

The whole parent component will re-render on input change in the child, which might be not an issue if the parent component is small / fast to re-render. The re-render performance of the parent component still can be an issue in the general case (for example large forms). This is solved problem in your case (see below).

State link pattern and no parent re-render are easier to implement using the 3rd party library, like Hookstate - supercharged React.useState to cover variety of use cases, including your's one. (Disclaimer: I am an author of the project).

Here is how it would look like with Hookstate. Child1 will change the input, Child2 will react to it. Parent will hold the state but will not re-render on state change, only Child1 and Child2 will.

import { useStateLink } from '@hookstate/core';

function Parent() {
    var state = useStateLink('initial input value');
    return <>
        <Child1 state={state} />
        <Child2 state={state}>
    </>
}

function Child1(props) {
    // to avoid parent re-render use local state,
    // could use `props.state` instead of `state` below instead
    var state = useStateLink(props.state)
    return <input
        value={state.get()}
        onChange={e => state.set(e.target.value)}
    />
}

function Child2(props) {
    // to avoid parent re-render use local state,
    // could use `props.state` instead of `state` below instead
    var state = useStateLink(props.state)
    return <p>Content of the state {state.get()}</p>
}

PS: there are many more examples here covering similar and more complicated scenarios, including deeply nested data, state validation, global state with setState hook, etc. There is also complete sample application online, which uses the Hookstate and the technique explained above.

Why maven? What are the benefits?

Figuring out dependencies for small projects is not hard. But once you start dealing with a dependency tree with hundreds of dependencies, things can easily get out of hand. (I'm speaking from experience here ...)

The other point is that if you use an IDE with incremental compilation and Maven support (like Eclipse + m2eclipse), then you should be able to set up edit/compile/hot deploy and test.

I personally don't do this because I've come to distrust this mode of development due to bad experiences in the past (pre Maven). Perhaps someone can comment on whether this actually works with Eclipse + m2eclipse.

Request redirect to /Account/Login?ReturnUrl=%2f since MVC 3 install on server

If nothing works then add authentication mode="Windows" in your system.web attribute in your Web.Config file. hope it will work for you.

Can I convert a boolean to Yes/No in a ASP.NET GridView

Add a method to your page class like this:

public string YesNo(bool active) 
{
  return active ? "Yes" : "No";
}

And then in your TemplateField you Bind using this method:

<%# YesNo(Active) %>

Check if a PHP cookie exists and if not set its value

Answer

You can't according to the PHP manual:

Once the cookies have been set, they can be accessed on the next page load with the $_COOKIE or $HTTP_COOKIE_VARS arrays.

This is because cookies are sent in response headers to the browser and the browser must then send them back with the next request. This is why they are only available on the second page load.

Work around

But you can work around it by also setting $_COOKIE when you call setcookie():

if(!isset($_COOKIE['lg'])) {
    setcookie('lg', 'ro');
    $_COOKIE['lg'] = 'ro';
}
echo $_COOKIE['lg'];

MySQL: Grant **all** privileges on database

To grant all priveleges on the database: mydb to the user: myuser, just execute:

GRANT ALL ON mydb.* TO 'myuser'@'localhost';

or:

GRANT ALL PRIVILEGES ON mydb.* TO 'myuser'@'localhost';

The PRIVILEGES keyword is not necessary.

Also I do not know why the other answers suggest that the IDENTIFIED BY 'password' be put on the end of the command. I believe that it is not required.

Specify multiple attribute selectors in CSS

Simple input[name=Sex][value=M] would do pretty nice. And it's actually well-described in the standard doc:

Multiple attribute selectors can be used to refer to several attributes of an element, or even several times to the same attribute.

Here, the selector matches all SPAN elements whose "hello" attribute has exactly the value "Cleveland" and whose "goodbye" attribute has exactly the value "Columbus":

span[hello="Cleveland"][goodbye="Columbus"] { color: blue; }

As a side note, using quotation marks around an attribute value is required only if this value is not a valid identifier.

JSFiddle Demo

Converting a sentence string to a string array of words in Java

Try using the following:

String str = "This is a simple sentence";
String[] strgs = str.split(" ");

That will create a substring at each index of the array of strings using the space as a split point.

Replacing a fragment with another fragment inside activity group

you can use simple code its work for transaction

Fragment newFragment = new MainCategoryFragment();
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.content_frame_NavButtom, newFragment);
ft.commit(); 

"Default Activity Not Found" on Android Studio upgrade

I got this error.

And found that in manifest file in launcher activity I did not put action and category in intent filter.

Wrong One:

<activity
android:name=".VideoAdStarter"
android:label="@string/app_name">

    <action android:name="android.intent.action.MAIN" />
    <category android:name="android.intent.category.LAUNCHER" />

</activity>

Right One:

<activity
android:name=".VideoAdStarter"
android:label="@string/app_name">

    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>

</activity>

A network-related or instance-specific error occurred while establishing a connection to SQL Server

Sql Server fire this error when your application don't have enough rights to access the database. there are several reason about this error . To fix this error you should follow the following instruction.

  1. Try to connect sql server from your server using management studio . if you use windows authentication to connect sql server then set your application pool identity to server administrator .

  2. if you use sql server authentication then check you connection string in web.config of your web application and set user id and password of sql server which allows you to log in .

  3. if your database in other server(access remote database) then first of enable remote access of sql server form sql server property from sql server management studio and enable TCP/IP form sql server configuration manager .

  4. after doing all these stuff and you still can't access the database then check firewall of server form where you are trying to access the database and add one rule in firewall to enable port of sql server(by default sql server use 1433 , to check port of sql server you need to check sql server configuration manager network protocol TCP/IP port).

  5. if your sql server is running on named instance then you need to write port number with sql serer name for example 117.312.21.21/nameofsqlserver,1433.

  6. If you are using cloud hosting like amazon aws or microsoft azure then server or instance will running behind cloud firewall so you need to enable 1433 port in cloud firewall if you have default instance or specific port for sql server for named instance.

  7. If you are using amazon RDS or SQL azure then you need to enable port from security group of that instance.

  8. If you are accessing sql server through sql server authentication mode them make sure you enabled "SQL Server and Windows Authentication Mode" sql server instance property. enter image description here

    1. Restart your sql server instance after making any changes in property as some changes will require restart.

if you further face any difficulty then you need to provide more information about your web site and sql server .

Is it possible to have placeholders in strings.xml for runtime values?

Yes! you can do so without writing any Java/Kotlin code, only XML by using this small library I created, which does so at buildtime, so your app won't be affected by it: https://github.com/LikeTheSalad/android-string-reference

Usage

Your strings:

<resources>
    <string name="app_name">My App Name</string>
    <string name="template_welcome_message">Welcome to ${app_name}</string>
</resources>

The generated string after building:

<!--resolved.xml-->
<resources>
    <string name="welcome_message">Welcome to My App Name</string>
</resources>

json.dumps vs flask.jsonify

The jsonify() function in flask returns a flask.Response() object that already has the appropriate content-type header 'application/json' for use with json responses. Whereas, the json.dumps() method will just return an encoded string, which would require manually adding the MIME type header.

See more about the jsonify() function here for full reference.

Edit: Also, I've noticed that jsonify() handles kwargs or dictionaries, while json.dumps() additionally supports lists and others.

jQuery AJAX file upload PHP

var formData = new FormData($("#YOUR_FORM_ID")[0]);
$.ajax({
    url: "upload.php",
    type: "POST",
    data : formData,
    processData: false,
    contentType: false,
    beforeSend: function() {

    },
    success: function(data){




    },
    error: function(xhr, ajaxOptions, thrownError) {
       console.log(thrownError + "\r\n" + xhr.statusText + "\r\n" + xhr.responseText);
    }
});

How to use Switch in SQL Server

This is a select statement, so each branch of the case must return something. If you want to perform actions, just use an if.

SQL Last 6 Months

Try this one

where datediff(month, datetime_column, getdate()) <= 6

To exclude or filter out future dates

where datediff(month, datetime_column, getdate()) between 0 and 6


This part datediff(month, datetime_column, getdate()) will get the month difference in number of current date and Datetime_Column and will return Rows like:

Result
1
2
3
4
5
6
7
8
9
10

This is Our final condition to get last 6 months data

where result <= 6

Java string replace and the NUL (NULL, ASCII 0) character?

Does replacing a character in a String with a null character even work in Java? I know that '\0' will terminate a c-string.

That depends on how you define what is working. Does it replace all occurrences of the target character with '\0'? Absolutely!

String s = "food".replace('o', '\0');
System.out.println(s.indexOf('\0')); // "1"
System.out.println(s.indexOf('d')); // "3"
System.out.println(s.length()); // "4"
System.out.println(s.hashCode() == 'f'*31*31*31 + 'd'); // "true"

Everything seems to work fine to me! indexOf can find it, it counts as part of the length, and its value for hash code calculation is 0; everything is as specified by the JLS/API.

It DOESN'T work if you expect replacing a character with the null character would somehow remove that character from the string. Of course it doesn't work like that. A null character is still a character!

String s = Character.toString('\0');
System.out.println(s.length()); // "1"
assert s.charAt(0) == 0;

It also DOESN'T work if you expect the null character to terminate a string. It's evident from the snippets above, but it's also clearly specified in JLS (10.9. An Array of Characters is Not a String):

In the Java programming language, unlike C, an array of char is not a String, and neither a String nor an array of char is terminated by '\u0000' (the NUL character).


Would this be the culprit to the funky characters?

Now we're talking about an entirely different thing, i.e. how the string is rendered on screen. Truth is, even "Hello world!" will look funky if you use dingbats font. A unicode string may look funky in one locale but not the other. Even a properly rendered unicode string containing, say, Chinese characters, may still look funky to someone from, say, Greenland.

That said, the null character probably will look funky regardless; usually it's not a character that you want to display. That said, since null character is not the string terminator, Java is more than capable of handling it one way or another.


Now to address what we assume is the intended effect, i.e. remove all period from a string, the simplest solution is to use the replace(CharSequence, CharSequence) overload.

System.out.println("A.E.I.O.U".replace(".", "")); // AEIOU

The replaceAll solution is mentioned here too, but that works with regular expression, which is why you need to escape the dot meta character, and is likely to be slower.

How can you change Network settings (IP Address, DNS, WINS, Host Name) with code in C#

The existing answers have quite broken code. The DNS method does not work at all. Here is code that I used to configure my NIC:

public static class NetworkConfigurator
{
    /// <summary>
    /// Set's a new IP Address and it's Submask of the local machine
    /// </summary>
    /// <param name="ipAddress">The IP Address</param>
    /// <param name="subnetMask">The Submask IP Address</param>
    /// <param name="gateway">The gateway.</param>
    /// <param name="nicDescription"></param>
    /// <remarks>Requires a reference to the System.Management namespace</remarks>
    public static void SetIP(string nicDescription, string[] ipAddresses, string subnetMask, string gateway)
    {
        using (var networkConfigMng = new ManagementClass("Win32_NetworkAdapterConfiguration"))
        {
            using (var networkConfigs = networkConfigMng.GetInstances())
            {
                foreach (var managementObject in networkConfigs.Cast<ManagementObject>().Where(mo => (bool)mo["IPEnabled"] && (string)mo["Description"] == nicDescription))
                {
                    using (var newIP = managementObject.GetMethodParameters("EnableStatic"))
                    {
                        // Set new IP address and subnet if needed
                        if (ipAddresses != null || !String.IsNullOrEmpty(subnetMask))
                        {
                            if (ipAddresses != null)
                            {
                                newIP["IPAddress"] = ipAddresses;
                            }

                            if (!String.IsNullOrEmpty(subnetMask))
                            {
                                newIP["SubnetMask"] = Array.ConvertAll(ipAddresses, _ => subnetMask);
                            }

                            managementObject.InvokeMethod("EnableStatic", newIP, null);
                        }

                        // Set mew gateway if needed
                        if (!String.IsNullOrEmpty(gateway))
                        {
                            using (var newGateway = managementObject.GetMethodParameters("SetGateways"))
                            {
                                newGateway["DefaultIPGateway"] = new[] { gateway };
                                newGateway["GatewayCostMetric"] = new[] { 1 };
                                managementObject.InvokeMethod("SetGateways", newGateway, null);
                            }
                        }
                    }
                }
            }
        }
    }

    /// <summary>
    /// Set's the DNS Server of the local machine
    /// </summary>
    /// <param name="nic">NIC address</param>
    /// <param name="dnsServers">Comma seperated list of DNS server addresses</param>
    /// <remarks>Requires a reference to the System.Management namespace</remarks>
    public static void SetNameservers(string nicDescription, string[] dnsServers)
    {
        using (var networkConfigMng = new ManagementClass("Win32_NetworkAdapterConfiguration"))
        {
            using (var networkConfigs = networkConfigMng.GetInstances())
            {
                foreach (var managementObject in networkConfigs.Cast<ManagementObject>().Where(mo => (bool)mo["IPEnabled"] && (string)mo["Description"] == nicDescription))
                {
                    using (var newDNS = managementObject.GetMethodParameters("SetDNSServerSearchOrder"))
                    {
                        newDNS["DNSServerSearchOrder"] = dnsServers;
                        managementObject.InvokeMethod("SetDNSServerSearchOrder", newDNS, null);
                    }
                }
            }
        }
    }
}

Exception thrown inside catch block - will it be caught again?

No, since the catches all refer to the same try block, so throwing from within a catch block would be caught by an enclosing try block (probably in the method that called this one)

Use child_process.execSync but keep output in console

Unless you redirect stdout and stderr as the accepted answer suggests, this is not possible with execSync or spawnSync. Without redirecting stdout and stderr those commands only return stdout and stderr when the command is completed.

To do this without redirecting stdout and stderr, you are going to need to use spawn to do this but it's pretty straight forward:

var spawn = require('child_process').spawn;

//kick off process of listing files
var child = spawn('ls', ['-l', '/']);

//spit stdout to screen
child.stdout.on('data', function (data) {   process.stdout.write(data.toString());  });

//spit stderr to screen
child.stderr.on('data', function (data) {   process.stdout.write(data.toString());  });

child.on('close', function (code) { 
    console.log("Finished with code " + code);
});

I used an ls command that recursively lists files so that you can test it quickly. Spawn takes as first argument the executable name you are trying to run and as it's second argument it takes an array of strings representing each parameter you want to pass to that executable.

However, if you are set on using execSync and can't redirect stdout or stderr for some reason, you can open up another terminal like xterm and pass it a command like so:

var execSync = require('child_process').execSync;

execSync("xterm -title RecursiveFileListing -e ls -latkR /");

This will allow you to see what your command is doing in the new terminal but still have the synchronous call.

How to save a pandas DataFrame table as a png

The following would need extensive customisation to format the table correctly, but the bones of it works:

import numpy as np
from PIL import Image, ImageDraw, ImageFont
import pandas as pd

df = pd.DataFrame({ 'A' : 1.,
                     'B' : pd.Series(1,index=list(range(4)),dtype='float32'),
                     'C' : np.array([3] * 4,dtype='int32'),
                     'D' : pd.Categorical(["test","train","test","train"]),
                     'E' : 'foo' })


class DrawTable():
    def __init__(self,_df):
        self.rows,self.cols = _df.shape
        img_size = (300,200)
        self.border = 50
        self.bg_col = (255,255,255)
        self.div_w = 1
        self.div_col = (128,128,128)
        self.head_w = 2
        self.head_col = (0,0,0)
        self.image = Image.new("RGBA", img_size,self.bg_col)
        self.draw = ImageDraw.Draw(self.image)
        self.draw_grid()
        self.populate(_df)
        self.image.show()
    def draw_grid(self):
        width,height = self.image.size
        row_step = (height-self.border*2)/(self.rows)
        col_step = (width-self.border*2)/(self.cols)
        for row in range(1,self.rows+1):
            self.draw.line((self.border-row_step//2,self.border+row_step*row,width-self.border,self.border+row_step*row),fill=self.div_col,width=self.div_w)
            for col in range(1,self.cols+1):
                self.draw.line((self.border+col_step*col,self.border-col_step//2,self.border+col_step*col,height-self.border),fill=self.div_col,width=self.div_w)
        self.draw.line((self.border-row_step//2,self.border,width-self.border,self.border),fill=self.head_col,width=self.head_w)
        self.draw.line((self.border,self.border-col_step//2,self.border,height-self.border),fill=self.head_col,width=self.head_w)
        self.row_step = row_step
        self.col_step = col_step
    def populate(self,_df2):
        font = ImageFont.load_default().font
        for row in range(self.rows):
            print(_df2.iloc[row,0])
            self.draw.text((self.border-self.row_step//2,self.border+self.row_step*row),str(_df2.index[row]),font=font,fill=(0,0,128))
            for col in range(self.cols):
                text = str(_df2.iloc[row,col])
                text_w, text_h = font.getsize(text)
                x_pos = self.border+self.col_step*(col+1)-text_w
                y_pos = self.border+self.row_step*row
                self.draw.text((x_pos,y_pos),text,font=font,fill=(0,0,128))
        for col in range(self.cols):
            text = str(_df2.columns[col])
            text_w, text_h = font.getsize(text)
            x_pos = self.border+self.col_step*(col+1)-text_w
            y_pos = self.border - self.row_step//2
            self.draw.text((x_pos,y_pos),text,font=font,fill=(0,0,128))
    def save(self,filename):
        try:
            self.image.save(filename,mode='RGBA')
            print(filename," Saved.")
        except:
            print("Error saving:",filename)




table1 = DrawTable(df)
table1.save('C:/Users/user/Pictures/table1.png')

The output looks like this:

enter image description here

Default parameters with C++ constructors

Matter of style, but as Matt said, definitely consider marking constructors with default arguments which would allow implicit conversion as 'explicit' to avoid unintended automatic conversion. It's not a requirement (and may not be preferable if you're making a wrapper class which you want to implicitly convert to), but it can prevent errors.

I personally like defaults when appropriate, because I dislike repeated code. YMMV.

java.lang.ClassNotFoundException: org.apache.log4j.Level

In my environment, I just added the two files to class path. And is work fine.

slf4j-jdk14-1.7.25.jar
slf4j-api-1.7.25.jar

Shell script variable not empty (-z option)

Of course it does. After replacing the variable, it reads [ !-z ], which is not a valid [ command. Use double quotes, or [[.

if [ ! -z "$errorstatus" ]

if [[ ! -z $errorstatus ]]

How to compare each item in a list with the rest, only once?

Your solution is correct, but your outer loop is still longer than needed. You don't need to compare the last element with anything else because it's been already compared with all the others in the previous iterations. Your inner loop still prevents that, but since we're talking about collision detection you can save the unnecessary check.

Using the same language you used to illustrate your algorithm, you'd come with something like this:

for (int i = 0, i < mylist.size() - 1; ++i)
    for (int j = i + 1, j < mylist.size(); --j)
        compare(mylist[i], mylist[j])

android - setting LayoutParams programmatically

after creating the view we have to add layout parameters .

change like this

TextView tv = new TextView(this);
tv.setLayoutParams(new ViewGroup.LayoutParams(
        ViewGroup.LayoutParams.WRAP_CONTENT,
        ViewGroup.LayoutParams.WRAP_CONTENT));

llview.addView(tv);
tv.setTextColor(Color.WHITE);
tv.setTextSize(2,25);
tv.setText(chat);
if (mine) {
    leftMargin = 5;
    tv.setBackgroundColor(0x7C5B77);
}
else {
    leftMargin = 50;
    tv.setBackgroundColor(0x778F6E);
}
final ViewGroup.MarginLayoutParams lpt =(MarginLayoutParams)tv.getLayoutParams();
lpt.setMargins(leftMargin,lpt.topMargin,lpt.rightMargin,lpt.bottomMargin);

SQL Server: Get table primary key using sql query

select * 
from sysobjects 
where xtype='pk' and 
   parent_obj in (select id from sysobjects where name='tablename')

this will work in sql 2005

How can I auto-elevate my batch file, so that it requests from UAC administrator rights if required?

There is an easy way without the need to use an external tool - it runs fine with Windows 7, 8, 8.1 and 10 and is backwards-compatible too (Windows XP doesn't have any UAC, thus elevation is not needed - in that case the script just proceeds).

Check out this code (I was inspired by the code by NIronwolf posted in the thread Batch File - "Access Denied" On Windows 7?), but I've improved it - in my version there isn't any directory created and removed to check for administrator privileges):

::::::::::::::::::::::::::::::::::::::::::::
:: Elevate.cmd - Version 4
:: Automatically check & get admin rights
:: see "https://stackoverflow.com/a/12264592/1016343" for description
::::::::::::::::::::::::::::::::::::::::::::
 @echo off
 CLS
 ECHO.
 ECHO =============================
 ECHO Running Admin shell
 ECHO =============================

:init
 setlocal DisableDelayedExpansion
 set cmdInvoke=1
 set winSysFolder=System32
 set "batchPath=%~0"
 for %%k in (%0) do set batchName=%%~nk
 set "vbsGetPrivileges=%temp%\OEgetPriv_%batchName%.vbs"
 setlocal EnableDelayedExpansion

:checkPrivileges
  NET FILE 1>NUL 2>NUL
  if '%errorlevel%' == '0' ( goto gotPrivileges ) else ( goto getPrivileges )

:getPrivileges
  if '%1'=='ELEV' (echo ELEV & shift /1 & goto gotPrivileges)
  ECHO.
  ECHO **************************************
  ECHO Invoking UAC for Privilege Escalation
  ECHO **************************************

  ECHO Set UAC = CreateObject^("Shell.Application"^) > "%vbsGetPrivileges%"
  ECHO args = "ELEV " >> "%vbsGetPrivileges%"
  ECHO For Each strArg in WScript.Arguments >> "%vbsGetPrivileges%"
  ECHO args = args ^& strArg ^& " "  >> "%vbsGetPrivileges%"
  ECHO Next >> "%vbsGetPrivileges%"

  if '%cmdInvoke%'=='1' goto InvokeCmd 

  ECHO UAC.ShellExecute "!batchPath!", args, "", "runas", 1 >> "%vbsGetPrivileges%"
  goto ExecElevation

:InvokeCmd
  ECHO args = "/c """ + "!batchPath!" + """ " + args >> "%vbsGetPrivileges%"
  ECHO UAC.ShellExecute "%SystemRoot%\%winSysFolder%\cmd.exe", args, "", "runas", 1 >> "%vbsGetPrivileges%"

:ExecElevation
 "%SystemRoot%\%winSysFolder%\WScript.exe" "%vbsGetPrivileges%" %*
 exit /B

:gotPrivileges
 setlocal & cd /d %~dp0
 if '%1'=='ELEV' (del "%vbsGetPrivileges%" 1>nul 2>nul  &  shift /1)

 ::::::::::::::::::::::::::::
 ::START
 ::::::::::::::::::::::::::::
 REM Run shell as admin (example) - put here code as you like
 ECHO %batchName% Arguments: P1=%1 P2=%2 P3=%3 P4=%4 P5=%5 P6=%6 P7=%7 P8=%8 P9=%9
 cmd /k

The script takes advantage of the fact that NET FILE requires administrator privilege and returns errorlevel 1 if you don't have it. The elevation is achieved by creating a script which re-launches the batch file to obtain privileges. This causes Windows to present the UAC dialog and asks you for the administrator account and password.

I have tested it with Windows 7, 8, 8.1, 10 and with Windows XP - it works fine for all. The advantage is, after the start point you can place anything that requires system administrator privileges, for example, if you intend to re-install and re-run a Windows service for debugging purposes (assumed that mypackage.msi is a service installer package):

msiexec /passive /x mypackage.msi
msiexec /passive /i mypackage.msi
net start myservice

Without this privilege elevating script, UAC would ask you three times for your administrator user and password - now you're asked only once at the beginning, and only if required.


If your script just needs to show an error message and exit if there aren't any administrator privileges instead of auto-elevating, this is even simpler: You can achieve this by adding the following at the beginning of your script:

@ECHO OFF & CLS & ECHO.
NET FILE 1>NUL 2>NUL & IF ERRORLEVEL 1 (ECHO You must right-click and select &
  ECHO "RUN AS ADMINISTRATOR"  to run this batch. Exiting... & ECHO. &
  PAUSE & EXIT /D)
REM ... proceed here with admin rights ...

This way, the user has to right-click and select "Run as administrator". The script will proceed after the REM statement if it detects administrator rights, otherwise exit with an error. If you don't require the PAUSE, just remove it. Important: NET FILE [...] EXIT /D) must be on the same line. It is displayed here in multiple lines for better readability!


On some machines, I've encountered issues, which are solved in the new version above already. One was due to different double quote handling, and the other issue was due to the fact that UAC was disabled (set to lowest level) on a Windows 7 machine, hence the script calls itself again and again.

I have fixed this now by stripping the quotes in the path and re-adding them later, and I've added an extra parameter which is added when the script re-launches with elevated rights.

The double quotes are removed by the following (details are here):

setlocal DisableDelayedExpansion
set "batchPath=%~0"
setlocal EnableDelayedExpansion

You can then access the path by using !batchPath!. It doesn't contain any double quotes, so it is safe to say "!batchPath!" later in the script.

The line

if '%1'=='ELEV' (shift & goto gotPrivileges)

checks if the script has already been called by the VBScript script to elevate rights, hence avoiding endless recursions. It removes the parameter using shift.


Update:

  • To avoid having to register the .vbs extension in Windows 10, I have replaced the line
    "%temp%\OEgetPrivileges.vbs"
    by
    "%SystemRoot%\System32\WScript.exe" "%temp%\OEgetPrivileges.vbs"
    in the script above; also added cd /d %~dp0 as suggested by Stephen (separate answer) and by Tomáš Zato (comment) to set script directory as default.

  • Now the script honors command line parameters being passed to it. Thanks to jxmallet, TanisDLJ and Peter Mortensen for observations and inspirations.

  • According to Artjom B.'s hint, I analyzed it and have replaced SHIFT by SHIFT /1, which preserves the file name for the %0 parameter

  • Added del "%temp%\OEgetPrivileges_%batchName%.vbs" to the :gotPrivileges section to clean up (as mlt suggested). Added %batchName% to avoid impact if you run different batches in parallel. Note that you need to use for to be able to take advantage of the advanced string functions, such as %%~nk, which extracts just the filename.

  • Optimized script structure, improvements (added variable vbsGetPrivileges which is now referenced everywhere allowing to change the path or name of the file easily, only delete .vbs file if batch needed to be elevated)

  • In some cases, a different calling syntax was required for elevation. If the script does not work, check the following parameters:
    set cmdInvoke=0
    set winSysFolder=System32
    Either change the 1st parameter to set cmdInvoke=1 and check if that already fixes the issue. It will add cmd.exe to the script performing the elevation.
    Or try to change the 2nd parameter to winSysFolder=Sysnative, this might help (but is in most cases not required) on 64 bit systems. (ADBailey has reported this). "Sysnative" is only required for launching 64-bit applications from a 32-bit script host (e.g. a Visual Studio build process, or script invocation from another 32-bit application).

  • To make it more clear how the parameters are interpreted, I am displaying it now like P1=value1 P2=value2 ... P9=value9. This is especially useful if you need to enclose parameters like paths in double quotes, e.g. "C:\Program Files".

  • If you want to debug the VBS script, you can add the //X parameter to WScript.exe as first parameter, as suggested here (it is described for CScript.exe, but works for WScript.exe too).

Useful links:

Is it possible to move/rename files in Git and maintain their history?

I would like to rename/move a project subtree in Git moving it from

/project/xyz

to

/components/xyz

If I use a plain git mv project components, then all the commit history for the xyz project gets lost.

No (8 years later, Git 2.19, Q3 2018), because Git will detect the directory rename, and this is now better documented.

See commit b00bf1c, commit 1634688, commit 0661e49, commit 4d34dff, commit 983f464, commit c840e1a, commit 9929430 (27 Jun 2018), and commit d4e8062, commit 5dacd4a (25 Jun 2018) by Elijah Newren (newren).
(Merged by Junio C Hamano -- gitster -- in commit 0ce5a69, 24 Jul 2018)

That is now explained in Documentation/technical/directory-rename-detection.txt:

Example:

When all of x/a, x/b and x/c have moved to z/a, z/b and z/c, it is likely that x/d added in the meantime would also want to move to z/d by taking the hint that the entire directory 'x' moved to 'z'.

But they are many other cases, like:

one side of history renames x -> z, and the other renames some file to x/e, causing the need for the merge to do a transitive rename.

To simplify directory rename detection, those rules are enforced by Git:

a couple basic rules limit when directory rename detection applies:

  1. If a given directory still exists on both sides of a merge, we do not consider it to have been renamed.
  2. If a subset of to-be-renamed files have a file or directory in the way (or would be in the way of each other), "turn off" the directory rename for those specific sub-paths and report the conflict to the user.
  3. If the other side of history did a directory rename to a path that your side of history renamed away, then ignore that particular rename from the other side of history for any implicit directory renames (but warn the user).

You can see a lot of tests in t/t6043-merge-rename-directories.sh, which also point out that:

  • a) If renames split a directory into two or more others, the directory with the most renames, "wins".
  • b) Avoid directory-rename-detection for a path, if that path is the source of a rename on either side of a merge.
  • c) Only apply implicit directory renames to directories if the other side of history is the one doing the renaming.

Spring Boot application can't resolve the org.springframework.boot package

This answer may be out of topic for most of readers. In my case the dependency didn't update and "mvn clean" didn't work since my wifi network at the office is highly securised, leaving a "connection timed out". (same respect github pushes and pulls don't work) I just moved to teathering with my phone and it works. Stupid, out of topic for most, but it may help some very specific cases.

Laravel - check if Ajax request

Those who prefer to use laravel helpers they can check if a request is ajax using laravel request() helper.

if(request()->ajax())
   // code

getting the table row values with jquery

$(document).ready(function () {
        $("#tbl_Customer tbody tr .companyname").click(function () {

            var comapnyname = $(this).closest(".trclass").find(".companyname").text();
            var CompanyAddress = $(this).closest(".trclass").find(".CompanyAddress").text();
            var CompanyEmail = $(this).closest(".trclass").find(".CompanyEmail").text();
            var CompanyContactNumber = $(this).closest(".trclass").find(".CompanyContactNumber").text();
            var CompanyContactPerson = $(this).closest(".trclass").find(".CompanyContactPerson").text();
           // var clickedCell = $(this);
            alert(comapnyname);
            alert(CompanyAddress);
            alert(CompanyEmail);
            alert(CompanyContactNumber);
            alert(CompanyContactPerson);

            //alert(clickedCell.text());
        });
    });

Display / print all rows of a tibble (tbl_df)

you can print it in Rstudio with View() more convenient:

df %>% View()

View(df)

Change status bar color with AppCompat ActionBarActivity

I don't think the status bar color has been implemented in AppCompat yet. These are the attributes which are available:

    <!-- ============= -->
    <!-- Color palette -->
    <!-- ============= -->

    <!-- The primary branding color for the app. By default, this is the color applied to the
         action bar background. -->
    <attr name="colorPrimary" format="color" />

    <!-- Dark variant of the primary branding color. By default, this is the color applied to
         the status bar (via statusBarColor) and navigation bar (via navigationBarColor). -->
    <attr name="colorPrimaryDark" format="color" />

    <!-- Bright complement to the primary branding color. By default, this is the color applied
         to framework controls (via colorControlActivated). -->
    <attr name="colorAccent" format="color" />

    <!-- The color applied to framework controls in their normal state. -->
    <attr name="colorControlNormal" format="color" />

    <!-- The color applied to framework controls in their activated (ex. checked) state. -->
    <attr name="colorControlActivated" format="color" />

    <!-- The color applied to framework control highlights (ex. ripples, list selectors). -->
    <attr name="colorControlHighlight" format="color" />

    <!-- The color applied to framework buttons in their normal state. -->
    <attr name="colorButtonNormal" format="color" />

    <!-- The color applied to framework switch thumbs in their normal state. -->
    <attr name="colorSwitchThumbNormal" format="color" />

(From \sdk\extras\android\support\v7\appcompat\res\values\attrs.xml)

Stacked bar chart

You need to transform your data to long format and shouldn't use $ inside aes:

DF <- read.table(text="Rank F1     F2     F3
1    500    250    50
2    400    100    30
3    300    155    100
4    200    90     10", header=TRUE)

library(reshape2)
DF1 <- melt(DF, id.var="Rank")

library(ggplot2)
ggplot(DF1, aes(x = Rank, y = value, fill = variable)) + 
  geom_bar(stat = "identity")

enter image description here

Import pfx file into particular certificate store from command line

To anyone else looking for this, I wasn't able to use certutil -importpfx into a specific store, and I didn't want to download the importpfx tool supplied by jaspernygaard's answer in order to avoid the requirement of copying the file to a large number of servers. I ended up finding my answer in a powershell script shown here.

The code uses System.Security.Cryptography.X509Certificates to import the certificate and then moves it into the desired store:

function Import-PfxCertificate { 

    param([String]$certPath,[String]$certRootStore = “localmachine”,[String]$certStore = “My”,$pfxPass = $null) 
    $pfx = new-object System.Security.Cryptography.X509Certificates.X509Certificate2 

    if ($pfxPass -eq $null) 
    {
        $pfxPass = read-host "Password" -assecurestring
    } 

    $pfx.import($certPath,$pfxPass,"Exportable,PersistKeySet") 

    $store = new-object System.Security.Cryptography.X509Certificates.X509Store($certStore,$certRootStore) 
    $store.open("MaxAllowed") 
    $store.add($pfx) 
    $store.close() 
}

Is recursion ever faster than looping?

In general, no, recursion will not be faster than a loop in any realistic usage that has viable implementations in both forms. I mean, sure, you could code up loops that take forever, but there would be better ways to implement the same loop that could outperform any implementation of the same problem via recursion.

You hit the nail on the head regarding the reason; creating and destroying stack frames is more expensive than a simple jump.

However, do note that I said "has viable implementations in both forms". For things like many sorting algorithms, there tends to not be a very viable way of implementing them that doesn't effectively set up its own version of a stack, due to the spawning of child "tasks" that are inherently part of the process. Thus, recursion may be just as fast as attempting to implement the algorithm via looping.

Edit: This answer is assuming non-functional languages, where most basic data types are mutable. It does not apply to functional languages.

How do I parse a URL into hostname and path in javascript?

today I meet this problem and I found: URL - MDN Web APIs

var url = new URL("http://test.example.com/dir/subdir/file.html#hash");

This return:

{ hash:"#hash", host:"test.example.com", hostname:"test.example.com", href:"http://test.example.com/dir/subdir/file.html#hash", origin:"http://test.example.com", password:"", pathname:"/dir/subdir/file.html", port:"", protocol:"http:", search: "", username: "" }

Hoping my first contribution helps you !

Appending a list or series to a pandas DataFrame as a row?

Converting the list to a data frame within the append function works, also when applied in a loop

import pandas as pd
mylist = [1,2,3]
df = pd.DataFrame()
df = df.append(pd.DataFrame(data[mylist]))

Compare string with all values in list

for word in d:
    if d in paid[j]:
         do_something()

will try all the words in the list d and check if they can be found in the string paid[j].

This is not very efficient since paid[j] has to be scanned again for each word in d. You could also use two sets, one composed of the words in the sentence, one of your list, and then look at the intersection of the sets.

sentence = "words don't come easy"
d = ["come", "together", "easy", "does", "it"]

s1 = set(sentence.split())
s2 = set(d)

print (s1.intersection(s2))

Output:

{'come', 'easy'}

Cannot find firefox binary in PATH. Make sure firefox is installed. OS appears to be: VISTA

This code simply worked for me

System.setProperty("webdriver.firefox.bin", "C:\\Program Files\\Mozilla Firefox 54\\firefox.exe");
String Firefoxdriverpath = "C:\\Users\\Hp\\Downloads\\geckodriver-v0.18.0-win64\\geckodriver.exe";
System.setProperty("webdriver.gecko.driver", Firefoxdriverpath);
DesiredCapabilities capabilities = DesiredCapabilities.firefox();
capabilities.setCapability("marionette", true);
driver = new FirefoxDriver(capabilities);

Using getopts to process long and short command line options

The built-in getopts can't do this. There is an external getopt(1) program that can do this, but you only get it on Linux from the util-linux package. It comes with an example script getopt-parse.bash.

There is also a getopts_long written as a shell function.

getApplication() vs. getApplicationContext()

It seems to have to do with context wrapping. Most classes derived from Context are actually a ContextWrapper, which essentially delegates to another context, possibly with changes by the wrapper.

The context is a general abstraction that supports mocking and proxying. Since many contexts are bound to a limited-lifetime object such as an Activity, there needs to be a way to get a longer-lived context, for purposes such as registering for future notifications. That is achieved by Context.getApplicationContext(). A logical implementation is to return the global Application object, but nothing prevents a context implementation from returning a wrapper or proxy with a suitable lifetime instead.

Activities and services are more specifically associated with an Application object. The usefulness of this, I believe, is that you can create and register in the manifest a custom class derived from Application and be certain that Activity.getApplication() or Service.getApplication() will return that specific object of that specific type, which you can cast to your derived Application class and use for whatever custom purpose.

In other words, getApplication() is guaranteed to return an Application object, while getApplicationContext() is free to return a proxy instead.

Using Tempdata in ASP.NET MVC - Best practice

Please note that MVC 3 onwards the persistence behavior of TempData has changed, now the value in TempData is persisted until it is read, and not just for the next request.

The value of TempData persists until it is read or until the session times out. Persisting TempData in this way enables scenarios such as redirection, because the values in TempData are available beyond a single request. https://msdn.microsoft.com/en-in/library/dd394711%28v=vs.100%29.aspx

Chrome says "Resource interpreted as script but transferred with MIME type text/plain.", what gives?

If you are using Spring MVC, you can add following mvn tag to exclude resources file from Spring Dispatch Servlet

<mvc:resources mapping="/js/*.js" location="/js/"/>
<mvc:resources mapping="/css/*.css" location="/css/"/>
<mvc:resources mapping="/images/*.*" location="/images/"/>

Is there a way to word-wrap long words in a div?

Most of the previous answer didn't work for me in Firefox 38.0.5. This did...

<div style='padding: 3px; width: 130px; word-break: break-all; word-wrap: break-word;'>
    // Content goes here
</div>

Documentation:

Convert string with comma to integer

How about this?

 "1,112".delete(',').to_i

Cannot ping AWS EC2 instance

When pinging two systems, by default SSH is enabled (if you have connected via putty or terminal.) To allow ping, I added the security group for each of the instance (inbound).

enter image description here

Add Auto-Increment ID to existing table?

ALTER TABLE `table` ADD `id` INT NOT NULL AUTO_INCREMENT unique

Try this. No need to drop your primary key.

How can I render HTML from another file in a React component?

If your template.html file is just HTML and not a React component, then you can't require it in the same way you would do with a JS file.

However, if you are using Browserify — there is a transform called stringify which will allow you to require non-js files as strings. Once you have added the transform, you will be able to require HTML files and they will export as though they were just strings.

Once you have required the HTML file, you'll have to inject the HTML string into your component, using the dangerouslySetInnerHTML prop.

var __html = require('./template.html');
var template = { __html: __html };

React.module.exports = React.createClass({
  render: function() {
    return(
      <div dangerouslySetInnerHTML={template} />
    );
  }
});

This goes against a lot of what React is about though. It would be more natural to create your templates as React components with JSX, rather than as regular HTML files.

The JSX syntax makes it trivially easy to express structured data, like HTML, especially when you use stateless function components.

If your template.html file looked something like this

<div class='foo'>
  <h1>Hello</h1>
  <p>Some paragraph text</p>
  <button>Click</button>
</div>

Then you could convert it instead to a JSX file that looked like this.

module.exports = function(props) {
  return (
    <div className='foo'>
      <h1>Hello</h1>
      <p>Some paragraph text</p>
      <button>Click</button>
    </div>
  );
};

Then you can require and use it without needing stringify.

var Template = require('./template');

module.exports = React.createClass({
  render: function() {
    var bar = 'baz';
    return(
      <Template foo={bar}/>
    );
  }
});

It maintains all of the structure of the original file, but leverages the flexibility of React's props model and allows for compile time syntax checking, unlike a regular HTML file.

ActionBar text color

Try a lot of methods, in the low version of the API,a feasible method is <item name="actionMenuTextColor">@color/your_color</item> and don't use the Android namespace,hope can help you

ps:

  <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <!-- Customize your theme here. -->
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
    <item name="actionMenuTextColor">@color/actionMenuTextColor</item>
</style>

what is the size of an enum type data in C++?

Because it's the size of an instance of the type - presumably enum values are stored as (32-bit / 4-byte) ints here.

How to break out from a ruby block?

I wanted to just be able to break out of a block - sort of like a forward goto, not really related to a loop. In fact, I want to break of of a block that is in a loop without terminating the loop. To do that, I made the block a one-iteration loop:

for b in 1..2 do
    puts b
    begin
        puts 'want this to run'
        break
        puts 'but not this'
    end while false
    puts 'also want this to run'
end

Hope this helps the next googler that lands here based on the subject line.

minimum double value in C/C++

- std::numeric_limits<double>::max()

should work just fine

Numeric limits

Link to download apache http server for 64bit windows.

From: http://wiki.apache.org/httpd/FAQ#Where_can_I_download_.28certified.29_64_bit_Apache_httpd_binaries_for_Windows.3F

Where can I download (certified) 64 bit Apache httpd binaries for Windows?

Right now, there are none. The Apache Software Foundation produces Open Source Software. The 32 bit binaries provided are a courtesy of the community members.

Though there are some unofficial e.g. http://www.apachelounge.com/download/win64/, but I have no idea if they can be trusted.

JAVA_HOME does not point to the JDK

This is by design. You cannot use ant's java.home (which is a java.lang.System property) interchangeably with how JAVA_HOME is set in the OS environment. You are probably trying to assert the location of the Java compiler with a fundamentally different value from a different property layer -- i.e. java.home (from Ant's Java internals) points to the Java Runtime Environment at <any_installed_java_pointed_to_by_ant>/jre while JDK_HOME (from the OS environment) is usually set to <DOWNLOADED_AND_INSTALLED_JAVA_DEVELOPMENT_KIT>.

See my question and answer here for more details: Where does Ant set its 'java.home' (and is it wrong) and is it supposed to append '/jre'?

The solution is to access the system environment property within Ant by using ${env.JAVA_HOME}. Specify which java to use explicitly in the Javac Task by setting the executable property to the javac path and the fork property to yes (see Ant's Javac Task Documentation). That way, it doesn't matter what Java environment Ant is running inside, the compiler is always clearly specified!

Android SQLite: Update Statement

You can use the code below.

String strFilter = "_id=" + Id;
ContentValues args = new ContentValues();
args.put(KEY_TITLE, title);
myDB.update("titles", args, strFilter, null);

How to convert hex strings to byte values in Java

String str[] = {"aa", "55"};

byte b[] = new byte[str.length];

for (int i = 0; i < str.length; i++) {
    b[i] = (byte) Integer.parseInt(str[i], 16);
}

Integer.parseInt(string, radix) converts a string into an integer, the radix paramter specifies the numeral system.

Use a radix of 16 if the string represents a hexadecimal number.
Use a radix of 2 if the string represents a binary number.
Use a radix of 10 (or omit the radix paramter) if the string represents a decimal number.

For further details check the Java docs: https://docs.oracle.com/javase/7/docs/api/java/lang/Integer.html#parseInt(java.lang.String,%20int)

Tomcat - maxThreads vs maxConnections

From Tomcat documentation, For blocking I/O (BIO), the default value of maxConnections is the value of maxThreads unless Executor (thread pool) is used in which case, the value of 'maxThreads' from Executor will be used instead. For Non-blocking IO, it doesn't seem to be dependent on maxThreads.

How to center an element horizontally and vertically

In order to vertically and horizontally center an element we can also use below mentioned properties.

This CSS property aligns-items vertically and accepts the following values:

flex-start: Items align to the top of the container.

flex-end: Items align to the bottom of the container.

center: Items align at the vertical center of the container.

baseline: Items display at the baseline of the container.

stretch: Items are stretched to fit the container.

This CSS property justify-content , which aligns items horizontally and accepts the following values:

flex-start: Items align to the left side of the container.

flex-end: Items align to the right side of the container.

center: Items align at the center of the container.

space-between: Items display with equal spacing between them.

space-around: Items display with equal spacing around them.

Apache Name Virtual Host with SSL

You may be able to replace the:

VirtualHost ipaddress:443

with

VirtualHost *:443

You probably need todo this on all of your virt hosts.

It will probably clear up that message. Let the ServerName directive worry about routing the message request.

Again, you may not be able to do this if you have multiple ip's aliases to the same machine.

Overriding !important style

Building on @Premasagar's excellent answer; if you don't want to remove all the other inline styles use this

//accepts the hyphenated versions (i.e. not 'cssFloat')
addStyle(element, property, value, important) {
    //remove previously defined property
    if (element.style.setProperty)
        element.style.setProperty(property, '');
    else
        element.style.setAttribute(property, '');

    //insert the new style with all the old rules
    element.setAttribute('style', element.style.cssText +
        property + ':' + value + ((important) ? ' !important' : '') + ';');
}

Can't use removeProperty() because it wont remove !important rules in Chrome.
Can't use element.style[property] = '' because it only accepts camelCase in FireFox.

The source was not found, but some or all event logs could not be searched

If you are performing a new install of the SenseNet TaskManagement website on IIS (from source code, not WebPI), you will get this message, usually related to SignalR communication. As @nicole-caliniou points out, it is due to a key search in the Registry that fails.

To solve this for SenseNet TaskManagement v1.1.0, first find the registry key name in the web.config file. By default it is "SnTaskWeb".

 <appSettings>
   <add key="LogSourceName" value="SnTaskWeb" />

Open the registry editor, regedit.exe, and navigate to HKLM\SYSTEM\CurrentControlSet\Services\EventLog\SnTask. Right-click on SnTask and select New Key, and name the key SnTaskWeb for the configuration shown above. Then right-click on the SnTaskWeb element and select New Expandable String Value. The name should be EventMessageFile and the value data should be C:\Windows\Microsoft.NET\Framework\v4.0.30319\EventLogMessages.dll.

Keywords: signalr, sensenet, regedit, permissions

Fragment pressing back button

This worked for me.

-Add .addToBackStack(null) when you call the new fragment from activity.

    FragmentTransaction mFragmentTransaction = getFragmentManager()
                .beginTransaction();
    ....
    mFragmentTransaction.addToBackStack(null);

-Add onBackPressed() to your activity

    @Override
public void onBackPressed() {
    if (getFragmentManager().getBackStackEntryCount() == 0) {
        this.finish();
    } else {
        getFragmentManager().popBackStack();
    }
}

How to add LocalDB to Visual Studio 2015 Community's SQL Server Object Explorer?

If you are not sure if local db is installed, or not sure which database name you should use to connect to it - try running 'sqllocaldb info' command - it will show you existing localdb databases.

Now, as far as I know, local db should be installed together with Visual Studio 2015. But probably it is not required feature, and if something goes wrong or it cannot be installed for some reason - Visual Studio installation continues still (note that is just my guess). So to be on the safe side don't rely on it will always be installed together with VS.

Blocks and yields in Ruby

I wanted to sort of add why you would do things that way to the already great answers.

No idea what language you are coming from, but assuming it is a static language, this sort of thing will look familiar. This is how you read a file in java

public class FileInput {

  public static void main(String[] args) {

    File file = new File("C:\\MyFile.txt");
    FileInputStream fis = null;
    BufferedInputStream bis = null;
    DataInputStream dis = null;

    try {
      fis = new FileInputStream(file);

      // Here BufferedInputStream is added for fast reading.
      bis = new BufferedInputStream(fis);
      dis = new DataInputStream(bis);

      // dis.available() returns 0 if the file does not have more lines.
      while (dis.available() != 0) {

      // this statement reads the line from the file and print it to
        // the console.
        System.out.println(dis.readLine());
      }

      // dispose all the resources after using them.
      fis.close();
      bis.close();
      dis.close();

    } catch (FileNotFoundException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
}

Ignoring the whole stream chaining thing, The idea is this

  1. Initialize resource that needs to be cleaned up
  2. use resource
  3. make sure to clean it up

This is how you do it in ruby

File.open("readfile.rb", "r") do |infile|
    while (line = infile.gets)
        puts "#{counter}: #{line}"
        counter = counter + 1
    end
end

Wildly different. Breaking this one down

  1. tell the File class how to initialize the resource
  2. tell the file class what to do with it
  3. laugh at the java guys who are still typing ;-)

Here, instead of handling step one and two, you basically delegate that off into another class. As you can see, that dramatically brings down the amount of code you have to write, which makes things easier to read, and reduces the chances of things like memory leaks, or file locks not getting cleared.

Now, its not like you can't do something similar in java, in fact, people have been doing it for decades now. It's called the Strategy pattern. The difference is that without blocks, for something simple like the file example, strategy becomes overkill due to the amount of classes and methods you need to write. With blocks, it is such a simple and elegant way of doing it, that it doesn't make any sense NOT to structure your code that way.

This isn't the only way blocks are used, but the others (like the Builder pattern, which you can see in the form_for api in rails) are similar enough that it should be obvious whats going on once you wrap your head around this. When you see blocks, its usually safe to assume that the method call is what you want to do, and the block is describing how you want to do it.

Error message "Forbidden You don't have permission to access / on this server"

I had this issue when using SSHFS to mount the files in my VirtualBox guest from my local filesystem before running a docker build. In the end, the "fix" was to copy all the files to the VirtualBox instance rather than building from inside the SSHFS mount, and then run the build from there.

How do I combine the first character of a cell with another cell in Excel?

Use following formula:

=CONCATENATE(LOWER(MID(A1,1,1)),LOWER( B1))

for

Josh Smith = jsmith

note that A1 contains name and B1 contains surname

Use Robocopy to copy only changed files?

To answer all your questions:

Can I use ROBOCOPY for this?

Yes, RC should fit your requirements (simplicity, only copy what needed)


What exactly does it mean to exclude?

It will exclude copying - RC calls it skipping


Would the /XO option copy only newer files, not files of the same age?

Yes, RC will only copy newer files. Files of the same age will be skipped.

(the correct command would be robocopy C:\SourceFolder D:\DestinationFolder ABC.dll /XO)


Maybe in your case using the /MIR option could be useful. In general RC is rather targeted at directories and directory trees than single files.

How to add "required" attribute to mvc razor viewmodel text input editor

I needed the "required" HTML5 atribute, so I did something like this:

<%: Html.TextBoxFor(model => model.Name, new { @required = true })%>

Performance of FOR vs FOREACH in PHP

It's 2020 and stuffs had greatly evolved with php 7.4 and opcache.

Here is the OP^ benchmark, ran as unix CLI, without the echo and html parts.

Test ran locally on a regular computer.

php -v

PHP 7.4.6 (cli) (built: May 14 2020 10:02:44) ( NTS )

Modified benchmark script:

<?php 
 ## preperations; just a simple environment state

  $test_iterations = 100;
  $test_arr_size = 1000;

  // a shared function that makes use of the loop; this should
  // ensure no funny business is happening to fool the test
  function test($input)
  {
    //echo '<!-- '.trim($input).' -->';
  }

  // for each test we create a array this should avoid any of the
  // arrays internal representation or optimizations from getting
  // in the way.

  // normal array
  $test_arr1 = array();
  $test_arr2 = array();
  $test_arr3 = array();
  // hash tables
  $test_arr4 = array();
  $test_arr5 = array();

  for ($i = 0; $i < $test_arr_size; ++$i)
  {
    mt_srand();
    $hash = md5(mt_rand());
    $key = substr($hash, 0, 5).$i;

    $test_arr1[$i] = $test_arr2[$i] = $test_arr3[$i] = $test_arr4[$key] = $test_arr5[$key]
      = $hash;
  }

  ## foreach

  $start = microtime(true);
  for ($j = 0; $j < $test_iterations; ++$j)
  {
    foreach ($test_arr1 as $k => $v)
    {
      test($v);
    }
  }
  echo 'foreach '.(microtime(true) - $start)."\n";  

  ## foreach (using reference)

  $start = microtime(true);
  for ($j = 0; $j < $test_iterations; ++$j)
  {
    foreach ($test_arr2 as &$value)
    {
      test($value);
    }
  }
  echo 'foreach (using reference) '.(microtime(true) - $start)."\n";

  ## for

  $start = microtime(true);
  for ($j = 0; $j < $test_iterations; ++$j)
  {
    $size = count($test_arr3);
    for ($i = 0; $i < $size; ++$i)
    {
      test($test_arr3[$i]);
    }
  }
  echo 'for '.(microtime(true) - $start)."\n";  

  ## foreach (hash table)

  $start = microtime(true);
  for ($j = 0; $j < $test_iterations; ++$j)
  {
    foreach ($test_arr4 as $k => $v)
    {
      test($v);
    }
  }
  echo 'foreach (hash table) '.(microtime(true) - $start)."\n";

  ## for (hash table)

  $start = microtime(true);
  for ($j = 0; $j < $test_iterations; ++$j)
  {
    $keys = array_keys($test_arr5);
    $size = sizeOf($test_arr5);
    for ($i = 0; $i < $size; ++$i)
    {
      test($test_arr5[$keys[$i]]);
    }
  }
  echo 'for (hash table) '.(microtime(true) - $start)."\n";

Output:

foreach 0.0032877922058105
foreach (using reference) 0.0029420852661133
for 0.0025191307067871
foreach (hash table) 0.0035080909729004
for (hash table) 0.0061779022216797

As you can see the evolution is insane, about 560 time faster than reported in 2012.

On my machines and servers, following my numerous experiments, basics for loops are the fastest. This is even clearer using nested loops ($i $j $k..)

It is also the most flexible in usage, and has a better readability from my view.

MySQL - How to increase varchar size of an existing column in a database without breaking existing data?

I am using mysql and below syntax worked well for me,

ALTER TABLE table_name MODIFY col_name VARCHAR(12);

How to sum array of numbers in Ruby?

array.reduce(0, :+)

While equivalent to array.inject(0, :+), the term reduce is entering a more common vernacular with the rise of MapReduce programming models.

inject, reduce, fold, accumulate, and compress are all synonymous as a class of folding functions. I find consistency across your code base most important, but since various communities tend to prefer one word over another, it’s nonetheless useful to know the alternatives.

To emphasize the map-reduce verbiage, here’s a version that is a little bit more forgiving on what ends up in that array.

array.map(&:to_i).reduce(0, :+)

Some additional relevant reading:

How do I use dataReceived event of the SerialPort Port Object in C#?

First off I recommend you use the following constructor instead of the one you currently use:

new SerialPort("COM10", 115200, Parity.None, 8, StopBits.One);

Next, you really should remove this code:

// Wait 10 Seconds for data...
for (int i = 0; i < 1000; i++)
{
    Thread.Sleep(10);
    Console.WriteLine(sp.Read(buf,0,bufSize)); //prints data directly to the Console
}

And instead just loop until the user presses a key or something, like so:

namespace serialPortCollection
{   class Program
    {
        static void Main(string[] args)
        {
            SerialPort sp = new SerialPort("COM10", 115200);
            sp.DataReceived += port_OnReceiveDatazz; // Add DataReceived Event Handler

            sp.Open();
            sp.WriteLine("$"); //Command to start Data Stream

            Console.ReadLine();

            sp.WriteLine("!"); //Stop Data Stream Command
            sp.Close();
        }

       // My Event Handler Method
        private static void port_OnReceiveDatazz(object sender, 
                                   SerialDataReceivedEventArgs e)
        {
            SerialPort spL = (SerialPort) sender;
            byte[] buf = new byte[spL.BytesToRead];
            Console.WriteLine("DATA RECEIVED!");
            spL.Read(buf, 0, buf.Length);
            foreach (Byte b in buf)
            {
                Console.Write(b.ToString());
            }
            Console.WriteLine();
        }
    }
}

Also, note the revisions to the data received event handler, it should actually print the buffer now.

UPDATE 1


I just ran the following code successfully on my machine (using a null modem cable between COM33 and COM34)

namespace TestApp
{
    class Program
    {
        static void Main(string[] args)
        {
            Thread writeThread = new Thread(new ThreadStart(WriteThread));
            SerialPort sp = new SerialPort("COM33", 115200, Parity.None, 8, StopBits.One);
            sp.DataReceived += port_OnReceiveDatazz; // Add DataReceived Event Handler

            sp.Open();
            sp.WriteLine("$"); //Command to start Data Stream

            writeThread.Start();

            Console.ReadLine();

            sp.WriteLine("!"); //Stop Data Stream Command
            sp.Close();
        }

        private static void port_OnReceiveDatazz(object sender, 
                                   SerialDataReceivedEventArgs e)
        {
            SerialPort spL = (SerialPort) sender;
            byte[] buf = new byte[spL.BytesToRead];
            Console.WriteLine("DATA RECEIVED!");
            spL.Read(buf, 0, buf.Length);
            foreach (Byte b in buf)
            {
                Console.Write(b.ToString() + " ");
            }
            Console.WriteLine();
        }

        private static void WriteThread()
        {
            SerialPort sp2 = new SerialPort("COM34", 115200, Parity.None, 8, StopBits.One);
            sp2.Open();
            byte[] buf = new byte[100];
            for (byte i = 0; i < 100; i++)
            {
                buf[i] = i;
            }
            sp2.Write(buf, 0, buf.Length);
            sp2.Close();
        }
    }
}

UPDATE 2


Given all of the traffic on this question recently. I'm beginning to suspect that either your serial port is not configured properly, or that the device is not responding.

I highly recommend you attempt to communicate with the device using some other means (I use hyperterminal frequently). You can then play around with all of these settings (bitrate, parity, data bits, stop bits, flow control) until you find the set that works. The documentation for the device should also specify these settings. Once I figured those out, I would make sure my .NET SerialPort is configured properly to use those settings.

Some tips on configuring the serial port:

Note that when I said you should use the following constructor, I meant that use that function, not necessarily those parameters! You should fill in the parameters for your device, the settings below are common, but may be different for your device.

new SerialPort("COM10", 115200, Parity.None, 8, StopBits.One);

It is also important that you setup the .NET SerialPort to use the same flow control as your device (as other people have stated earlier). You can find more info here:

http://www.lammertbies.nl/comm/info/RS-232_flow_control.html

Sieve of Eratosthenes - Finding Primes Python

A simple speed hack: when you define the variable "primes," set the step to 2 to skip all even numbers automatically, and set the starting point to 1.

Then you can further optimize by instead of for i in primes, use for i in primes[:round(len(primes) ** 0.5)]. That will dramatically increase performance. In addition, you can eliminate numbers ending with 5 to further increase speed.

How do I deserialize a complex JSON object in C# .NET?

First install newtonsoft.json package to Visual Studio using NuGet Package Manager then add the following code:

ClassName ObjectName = JsonConvert.DeserializeObject < ClassName > (jsonObject);

COUNT DISTINCT with CONDITIONS

You can try this:

select
  count(distinct tag) as tag_count,
  count(distinct (case when entryId > 0 then tag end)) as positive_tag_count
from
  your_table_name;

The first count(distinct...) is easy. The second one, looks somewhat complex, is actually the same as the first one, except that you use case...when clause. In the case...when clause, you filter only positive values. Zeros or negative values would be evaluated as null and won't be included in count.

One thing to note here is that this can be done by reading the table once. When it seems that you have to read the same table twice or more, it can actually be done by reading once, in most of the time. As a result, it will finish the task a lot faster with less I/O.

Regex to validate password strength

You should also consider changing some of your rules to:

  1. Add more special characters i.e. %, ^, (, ), -, _, +, and period. I'm adding all the special characters that you missed above the number signs in US keyboards. Escape the ones regex uses.
  2. Make the password 8 or more characters. Not just a static number 8.

With the above improvements, and for more flexibility and readability, I would modify the regex to.

^(?=(.*[a-z]){3,})(?=(.*[A-Z]){2,})(?=(.*[0-9]){2,})(?=(.*[!@#$%^&*()\-__+.]){1,}).{8,}$

Basic Explanation

(?=(.*RULE){MIN_OCCURANCES,})     

Each rule block is shown by (?=(){}). The rule and number of occurrences can then be easily specified and tested separately, before getting combined

Detailed Explanation

^                               start anchor
(?=(.*[a-z]){3,})               lowercase letters. {3,} indicates that you want 3 of this group
(?=(.*[A-Z]){2,})               uppercase letters. {2,} indicates that you want 2 of this group
(?=(.*[0-9]){2,})               numbers. {2,} indicates that you want 2 of this group
(?=(.*[!@#$%^&*()\-__+.]){1,})  all the special characters in the [] fields. The ones used by regex are escaped by using the \ or the character itself. {1,} is redundant, but good practice, in case you change that to more than 1 in the future. Also keeps all the groups consistent
{8,}                            indicates that you want 8 or more
$                               end anchor

And lastly, for testing purposes here is a robulink with the above regex

How to create an executable .exe file from a .m file

Try:

mcc -m yourfile

Also see help mcc

java.lang.RuntimeException: Unable to instantiate org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient

I did below modifications and I am able to start the Hive Shell without any errors:

1. ~/.bashrc

Inside bashrc file add the below environment variables at End Of File : sudo gedit ~/.bashrc

#Java Home directory configuration
export JAVA_HOME="/usr/lib/jvm/java-9-oracle"
export PATH="$PATH:$JAVA_HOME/bin"

# Hadoop home directory configuration
export HADOOP_HOME=/usr/local/hadoop
export PATH=$PATH:$HADOOP_HOME/bin
export PATH=$PATH:$HADOOP_HOME/sbin

export HIVE_HOME=/usr/lib/hive
export PATH=$PATH:$HIVE_HOME/bin

2. hive-site.xml

You have to create this file(hive-site.xml) in conf directory of Hive and add the below details

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>

<property>
  <name>javax.jdo.option.ConnectionURL</name>
  <value>jdbc:mysql://localhost/metastore?createDatabaseIfNotExist=true</value>
</property>


<property>
  <name>javax.jdo.option.ConnectionDriverName</name>
  <value>com.mysql.jdbc.Driver</value>
</property>

<property>
  <name>javax.jdo.option.ConnectionUserName</name>
  <value>root</value>
</property>

<property>
  <name>javax.jdo.option.ConnectionPassword</name>
  <value>root</value>
</property>

<property>
  <name>datanucleus.autoCreateSchema</name>
  <value>true</value>
</property>

<property>
  <name>datanucleus.fixedDatastore</name>
  <value>true</value>
</property>

<property>
 <name>datanucleus.autoCreateTables</name>
 <value>True</value>
 </property>

</configuration>

3. You also need to put the jar file(mysql-connector-java-5.1.28.jar) in the lib directory of Hive

4. Below installations required on your Ubuntu to Start the Hive Shell:

  1. MySql
  2. Hadoop
  3. Hive
  4. Java

5. Execution Part:

  1. Start all services of Hadoop: start-all.sh

  2. Enter the jps command to check whether all Hadoop services are up and running: jps

  3. Enter the hive command to enter into hive shell: hive

Uncaught SoapFault exception: [HTTP] Error Fetching http headers

There is an issue in php version less than 5.2.6. You may need to upgrade the version of php.

How to convert array values to lowercase in PHP?

use array_map():

$yourArray = array_map('strtolower', $yourArray);

In case you need to lowercase nested array (by Yahya Uddin):

$yourArray = array_map('nestedLowercase', $yourArray);

function nestedLowercase($value) {
    if (is_array($value)) {
        return array_map('nestedLowercase', $value);
    }
    return strtolower($value);
}

Disallow Twitter Bootstrap modal window from closing

<button type="button" class="btn btn-info btn-md" id="myBtn3">Static 
Modal</button>

<!-- Modal -->
<div class="modal fade" id="myModal3" role="dialog">
<div class="modal-dialog">
  <!-- Modal content-->
  <div class="modal-content">
    <div class="modal-header">
      <button type="button" class="close" data-dismiss="modal">×</button>
      <h4 class="modal-title">Static Backdrop</h4>
    </div>
    <div class="modal-body">
      <p>You cannot click outside of this modal to close it.</p>
    </div>
    <div class="modal-footer">
      <button type="button" class="btn btn-default" data-
      dismiss="modal">Close</button>
    </div>
   </div>
  </div>
</div>
   <script>
    $("#myBtn3").click(function(){
     $("#myModal3").modal({backdrop: "static"});
    });
   });
  </script>

Centos/Linux setting logrotate to maximum file size for all logs

As mentioned by Zeeshan, the logrotate options size, minsize, maxsize are triggers for rotation.

To better explain it. You can run logrotate as often as you like, but unless a threshold is reached such as the filesize being reached or the appropriate time passed, the logs will not be rotated.

The size options do not ensure that your rotated logs are also of the specified size. To get them to be close to the specified size you need to call the logrotate program sufficiently often. This is critical.

For log files that build up very quickly (e.g. in the hundreds of MB a day), unless you want them to be very large you will need to ensure logrotate is called often! this is critical.

Therefore to stop your disk filling up with multi-gigabyte log files you need to ensure logrotate is called often enough, otherwise the log rotation will not work as well as you want.

on Ubuntu, you can easily switch to hourly rotation by moving the script /etc/cron.daily/logrotate to /etc/cron.hourly/logrotate

Or add

*/5 * * * * /etc/cron.daily/logrotate 

To your /etc/crontab file. To run it every 5 minutes.

The size option ignores the daily, weekly, monthly time options. But minsize & maxsize take it into account.

The man page is a little confusing there. Here's my explanation.

minsize rotates only when the file has reached an appropriate size and the set time period has passed. e.g. minsize 50MB + daily If file reaches 50MB before daily time ticked over, it'll keep growing until the next day.

maxsize will rotate when the log reaches a set size or the appropriate time has passed. e.g. maxsize 50MB + daily. If file is 50MB and we're not at the next day yet, the log will be rotated. If the file is only 20MB and we roll over to the next day then the file will be rotated.

size will rotate when the log > size. Regardless of whether hourly/daily/weekly/monthly is specified. So if you have size 100M - it means when your log file is > 100M the log will be rotated if logrotate is run when this condition is true. Once it's rotated, the main log will be 0, and a subsequent run will do nothing.

So in the op's case. Specficially 50MB max I'd use something like the following:

/var/log/logpath/*.log {
    maxsize 50M
    hourly
    missingok
    rotate 8
    compress
    notifempty
    nocreate
}

Which means he'd create 8hrs of logs max. And there would be 8 of them at no more than 50MB each. Since he's saying that he's getting multi gigabytes each day and assuming they build up at a fairly constant rate, and maxsize is used he'll end up with around close to the max reached for each file. So they will be likely close to 50MB each. Given the volume they build, he would need to ensure that logrotate is run often enough to meet the target size.

Since I've put hourly there, we'd need logrotate to be run a minimum of every hour. But since they build up to say 2 gigabytes per day and we want 50MB... assuming a constant rate that's 83MB per hour. So you can imagine if we run logrotate every hour, despite setting maxsize to 50 we'll end up with 83MB log's in that case. So in this instance set the running to every 30 minutes or less should be sufficient.

Ensure logrotate is run every 30 mins.

*/30 * * * * /etc/cron.daily/logrotate 

Difference between @click and v-on:click Vuejs

v-bind and v-on are two frequently used directives in vuejs html template. So they provided a shorthand notation for the both of them as follows:

You can replace v-on: with @

v-on:click='someFunction'

as:

@click='someFunction'

Another example:

v-on:keyup='someKeyUpFunction'

as:

@keyup='someKeyUpFunction'

Similarly, v-bind with :

v-bind:href='var1'

Can be written as:

:href='var1'

Hope it helps!

What in layman's terms is a Recursive Function using PHP

An example would be to print every file in any subdirectories of a given directory (if you have no symlinks inside these directories which may break the function somehow). A pseudo-code of printing all files looks like this:

function printAllFiles($dir) {
    foreach (getAllDirectories($dir) as $f) {
        printAllFiles($f); // here is the recursive call
    }
    foreach (getAllFiles($dir) as $f) {
        echo $f;
    }
}

The idea is to print all sub directories first and then the files of the current directory. This idea get applied to all sub directories, and thats the reason for calling this function recursively for all sub directories.

If you want to try this example you have to check for the special directories . and .., otherwise you get stuck in calling printAllFiles(".") all the time. Additionally you must check what to print and what your current working directory is (see opendir(), getcwd(), ...).

ImportError: No module named BeautifulSoup

I had the same problem with eclipse on windows 10.

I installed it like recommende over the windows command window (cmd) with:

C:\Users\NAMEOFUSER\AppData\Local\Programs\Python\beautifulsoup4-4.8.2\setup.py install 

BeautifulSoup was install like this in my python directory:

C:\Users\NAMEOFUSE\AppData\Local\Programs\Python\Python38\Lib\site-packages\beautifulsoup4-4.8.2-py3.8.egg

After manually coping the bs4 and EGG-INFO folders into the site-packages folder everything started to work, also the example:

from bs4 import BeautifulSoup


html = """
    <html>
        <body>
            <p> Ich bin ein Absatz!</p>
        </body>
    </html>
"""
print(html)


soup = BeautifulSoup(html, 'html.parser')

print(soup.find_all("p"))

UDP vs TCP, how much faster is it?

Which protocol performs better (in terms of throughput) - UDP or TCP - really depends on the network characteristics and the network traffic. Robert S. Barnes, for example, points out a scenario where TCP performs better (small-sized writes). Now, consider a scenario in which the network is congested and has both TCP and UDP traffic. Senders in the network that are using TCP, will sense the 'congestion' and cut down on their sending rates. However, UDP doesn't have any congestion avoidance or congestion control mechanisms, and senders using UDP would continue to pump in data at the same rate. Gradually, TCP senders would reduce their sending rates to bare minimum and if UDP senders have enough data to be sent over the network, they would hog up the majority of bandwidth available. So, in such a case, UDP senders will have greater throughput, as they get the bigger pie of the network bandwidth. In fact, this is an active research topic - How to improve TCP throughput in presence of UDP traffic. One way, that I know of, using which TCP applications can improve throughput is by opening multiple TCP connections. That way, even though, each TCP connection's throughput might be limited, the sum total of the throughput of all TCP connections may be greater than the throughput for an application using UDP.

How to get first/top row of the table in Sqlite via Sql Query

Use the following query:

SELECT * FROM SAMPLE_TABLE ORDER BY ROWID ASC LIMIT 1

Note: Sqlite's row id references are detailed here.

Python exit commands - why so many and when should each be used?

sys.exit is the canonical way to exit.

Internally sys.exit just raises SystemExit. However, calling sys.exitis more idiomatic than raising SystemExit directly.

os.exit is a low-level system call that exits directly without calling any cleanup handlers.

quit and exit exist only to provide an easy way out of the Python prompt. This is for new users or users who accidentally entered the Python prompt, and don't want to know the right syntax. They are likely to try typing exit or quit. While this will not exit the interpreter, it at least issues a message that tells them a way out:

>>> exit
Use exit() or Ctrl-D (i.e. EOF) to exit
>>> exit()
$

This is essentially just a hack that utilizes the fact that the interpreter prints the __repr__ of any expression that you enter at the prompt.

Sort an ArrayList based on an object field

Use a custom comparator:

Collections.sort(nodeList, new Comparator<DataNode>(){
     public int compare(DataNode o1, DataNode o2){
         if(o1.degree == o2.degree)
             return 0;
         return o1.degree < o2.degree ? -1 : 1;
     }
});

Failed to serialize the response in Web API with Json

public class UserController : ApiController
{

   Database db = new Database();

   // construction
   public UserController()
   {
      // Add the following code
      // problem will be solved
      db.Configuration.ProxyCreationEnabled = false;
   }

   public IEnumerable<User> GetAll()
    {
            return db.Users.ToList();
    }
}

Java reflection: how to get field value from an object, not knowing its class

There is one more way, i got the same situation in my project. i solved this way

List<Object[]> list = HQL.list();

In above hibernate query language i know at which place what are my objects so what i did is :

for(Object[] obj : list){
String val = String.valueOf(obj[1]);
int code =Integer.parseint(String.valueof(obj[0]));
}

this way you can get the mixed objects with ease, but you should know in advance at which place what value you are getting or you can just check by printing the values to know. sorry for the bad english I hope this help

Iterator invalidation rules

C++11 (Source: Iterator Invalidation Rules (C++0x))


Insertion

Sequence containers

  • vector: all iterators and references before the point of insertion are unaffected, unless the new container size is greater than the previous capacity (in which case all iterators and references are invalidated) [23.3.6.5/1]
  • deque: all iterators and references are invalidated, unless the inserted member is at an end (front or back) of the deque (in which case all iterators are invalidated, but references to elements are unaffected) [23.3.3.4/1]
  • list: all iterators and references unaffected [23.3.5.4/1]
  • forward_list: all iterators and references unaffected (applies to insert_after) [23.3.4.5/1]
  • array: (n/a)

Associative containers

  • [multi]{set,map}: all iterators and references unaffected [23.2.4/9]

Unsorted associative containers

  • unordered_[multi]{set,map}: all iterators invalidated when rehashing occurs, but references unaffected [23.2.5/8]. Rehashing does not occur if the insertion does not cause the container's size to exceed z * B where z is the maximum load factor and B the current number of buckets. [23.2.5/14]

Container adaptors

  • stack: inherited from underlying container
  • queue: inherited from underlying container
  • priority_queue: inherited from underlying container

Erasure

Sequence containers

  • vector: every iterator and reference at or after the point of erase is invalidated [23.3.6.5/3]
  • deque: erasing the last element invalidates only iterators and references to the erased elements and the past-the-end iterator; erasing the first element invalidates only iterators and references to the erased elements; erasing any other elements invalidates all iterators and references (including the past-the-end iterator) [23.3.3.4/4]
  • list: only the iterators and references to the erased element is invalidated [23.3.5.4/3]
  • forward_list: only the iterators and references to the erased element is invalidated (applies to erase_after) [23.3.4.5/1]
  • array: (n/a)

Associative containers

  • [multi]{set,map}: only iterators and references to the erased elements are invalidated [23.2.4/9]

Unordered associative containers

  • unordered_[multi]{set,map}: only iterators and references to the erased elements are invalidated [23.2.5/13]

Container adaptors

  • stack: inherited from underlying container
  • queue: inherited from underlying container
  • priority_queue: inherited from underlying container

Resizing

  • vector: as per insert/erase [23.3.6.5/12]
  • deque: as per insert/erase [23.3.3.3/3]
  • list: as per insert/erase [23.3.5.3/1]
  • forward_list: as per insert/erase [23.3.4.5/25]
  • array: (n/a)

Note 1

Unless otherwise specified (either explicitly or by defining a function in terms of other functions), invoking a container member function or passing a container as an argument to a library function shall not invalidate iterators to, or change the values of, objects within that container. [23.2.1/11]

Note 2

no swap() function invalidates any references, pointers, or iterators referring to the elements of the containers being swapped. [ Note: The end() iterator does not refer to any element, so it may be invalidated. —end note ] [23.2.1/10]

Note 3

Other than the above caveat regarding swap(), it's not clear whether "end" iterators are subject to the above listed per-container rules; you should assume, anyway, that they are.

Note 4

vector and all unordered associative containers support reserve(n) which guarantees that no automatic resizing will occur at least until the size of the container grows to n. Caution should be taken with unordered associative containers because a future proposal will allow the specification of a minimum load factor, which would allow rehashing to occur on insert after enough erase operations reduce the container size below the minimum; the guarantee should be considered potentially void after an erase.

Trying to load local JSON file to show data in a html page using JQuery

app.js

$("button").click( function() {
 $.getJSON( "article.json", function(obj) {
  $.each(obj, function(key, value) {
         $("ul").append("<li>"+value.name+"'s age is : "+value.age+"</li>");
  });
 });
});

index.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Tax Calulator</title>
    <script src="jquery-3.2.0.min.js" type="text/javascript"></script>
  </head>
  <body>
    <ul></ul>
    <button>Users</button>
<script type="text/javascript" src="app.js"></script>
  </body>
</html>

article.json

{
"a": {
"name": "Abra",
"age": 125,
"company": "Dabra"
},
"b": {
"name": "Tudak tudak",
"age": 228,
"company": "Dhidak dhidak"
}
}

server.js

var http = require('http');
var fs = require('fs');

function onRequest(request,response){
  if(request.method == 'GET' && request.url == '/') {
          response.writeHead(200,{"Content-Type":"text/html"});
          fs.createReadStream("./index.html").pipe(response);
  } else if(request.method == 'GET' && request.url == '/jquery-3.2.0.min.js') {
          response.writeHead(200,{"Content-Type":"text/javascript"});
          fs.createReadStream("./jquery-3.2.0.min.js").pipe(response);
  } else if(request.method == 'GET' && request.url == '/app.js') {
          response.writeHead(200,{"Content-Type":"text/javascript"});
          fs.createReadStream("./app.js").pipe(response);
  }
  else if(request.method == 'GET' && request.url == '/article.json') {
          response.writeHead(200,{"Content-Type":"text/json"});
          fs.createReadStream("./article.json").pipe(response);
  }
}

http.createServer(onRequest).listen(2341);
console.log("Server is running ....");

Server.js will run a simple node http server in your local to process the data.

Note don't forget toa dd jQuery library in your folder structure and change the version number accordingly in server.js and index.html

This is my running one https://github.com/surya4/jquery-json.

How can I run an EXE program from a Windows Service using C#?

System.Diagnostics.Process.Start("Exe Name");

call a static method inside a class?

In the later PHP version self::staticMethod(); also will not work. It will throw the strict standard error.

In this case, we can create object of same class and call by object

here is the example

class Foo {

    public function fun1() {
        echo 'non-static';   
    }

    public static function fun2() {
        echo (new self)->fun1();
    }
}

Disable Enable Trigger SQL server for a table

Below is the simplest way

Try the code

ALTER TRIGGER trigger_name DISABLE

That's it :)

How to make an authenticated web request in Powershell?

The PowerShell is almost exactly the same.

$webclient = new-object System.Net.WebClient
$webclient.Credentials = new-object System.Net.NetworkCredential($username, $password, $domain)
$webpage = $webclient.DownloadString($url)

How to insert text with single quotation sql server 2005

The answer really depends on how you are doing the INSERT.

If you are specifying a SQL literal then you need to use the double-tick approach:

-- Direct insert
INSERT INTO Table1 (Column1) VALUES ('John''s')

-- Using a parameter, with a direct insert
DECLARE @Value varchar(50)
SET @Value = 'John''s'
INSERT INTO Table1 (Column1) VALUES (@Value)

-- Using a parameter, with dynamic SQL
DECLARE @Value varchar(50)
SET @Value = 'John''s'
EXEC sp_executesql 'INSERT INTO Table1 (Column1) VALUES (@p1)', '@p1 varchar(50)', @Value

If you are doing the INSERT from code, use parameters:

// Sample ADO.NET
using (SqlConnection conn = new SqlConnection(connectionString)) {
    conn.Open();
    using (SqlCommand command = conn.CreateCommand()) {
        command.CommandText = "INSERT INTO Table1 (Column1) VALUES (@Value)";

        command.Parameters.AddWithValue("@Value", "John's");

        command.ExecuteNonQuery();
    }
}

If your data contains user-input, direct or indirect, USE PARAMETERS. Parameters protect against SQL Injection attacks. Never ever build up dynamic SQL with user-input.

When should we call System.exit in Java

System.exit is needed

  • when you want to return a non-0 error code
  • when you want to exit your program from somewhere that isn't main()

In your case, it does the exact same thing as the simple return-from-main.

start MySQL server from command line on Mac OS Lion

MySql server startup error 'The server quit without updating PID file '

if you have installed mysql from homebrew

close mysql server from preferences of mac

ps ax | grep mysql

#kill all the mysql process running
sudo kill -9 pid

which mysql
/usr/local/bin/mysql
Admins-MacBook-Pro:bin username$ sudo mysql.server start

Starting MySQL
. SUCCESS! 

Admins-MacBook-Pro:bin username$ which mysql

/usr/local/bin/mysql

Admins-MacBook-Pro:bin username$ ps ax | grep mysql

54916 s005  S      0:00.02 /bin/sh 
/usr/local/Cellar/[email protected]/5.7.27_1/bin/mysqld_safe --datadir=/usr/local/var/mysql --pid-file=/usr/local/var/mysql/Admins-MacBook-Pro.local.pid
55012 s005  S      0:00.40 /usr/local/Cellar/[email protected]/5.7.27_1/bin/mysqld --basedir=/usr/local/Cellar/[email protected]/5.7.27_1 --datadir=/usr/local/var/mysql --plugin-dir=/usr/local/Cellar/[email protected]/5.7.27_1/lib/plugin --user=mysql --log-error=Admins-MacBook-Pro.local.err --pid-file=/usr/local/var/mysql/Admins-MacBook-Pro.local.pid
55081 s005  S+     0:00.00 grep mysql

CMake error at CMakeLists.txt:30 (project): No CMAKE_C_COMPILER could be found

This works for me in Ubuntu 17.10 (Artful Aardvark):

apt-get update
apt-get install build-essential

Xcode doesn't see my iOS device but iTunes does

Had same problem with some non-licensed cables. Works fine with Apple's & Belkin's USB cables.

Regular Expressions: Search in list

To do so without compiling the Regex first, use a lambda function - for example:

from re import match

values = ['123', '234', 'foobar']
filtered_values = list(filter(lambda v: match('^\d+$', v), values))

print(filtered_values)

Returns:

['123', '234']

filter() just takes a callable as it's first argument, and returns a list where that callable returned a 'truthy' value.

Is it possible to install another version of Python to Virtualenv?

This procedure installs Python2.7 anywhere and eliminates any absolute path references within your env folder (managed by virtualenv). Even virtualenv isn't installed absolutely.

Thus, theoretically, you can drop the top level directory into a tarball, distribute, and run anything configured within the tarball on a machine that doesn't have Python (or any dependencies) installed.

Contact me with any questions. This is just part of an ongoing, larger project I am engineering. Now, for the drop...

  1. Set up environment folders.

    $ mkdir env
    $ mkdir pyenv
    $ mkdir dep
    
  2. Get Python-2.7.3, and virtualenv without any form of root OS installation.

    $ cd dep
    $ wget http://www.python.org/ftp/python/2.7.3/Python-2.7.3.tgz
    $ wget https://raw.github.com/pypa/virtualenv/master/virtualenv.py
    
  3. Extract and install Python-2.7.3 into the pyenv dir. make clean is optional if you are doing this a 2nd, 3rd, Nth time...

    $ tar -xzvf Python-2.7.3.tgz
    $ cd Python-2.7.3
    $ make clean
    $ ./configure --prefix=/path/to/pyenv
    $ make && make install
    $ cd ../../
    $ ls
    dep    env    pyenv
    
  4. Create your virtualenv

    $ dep/virtualenv.py --python=/path/to/pyenv/bin/python --verbose env
    
  5. Fix the symlink to python2.7 within env/include/

    $ ls -l env/include/
    $ cd !$
    $ rm python2.7
    $ ln -s ../../pyenv/include/python2.7 python2.7
    $ cd ../../
    
  6. Fix the remaining python symlinks in env. You'll have to delete the symbolically linked directories and recreate them, as above. Also, here's the syntax to force in-place symbolic link creation.

    $ ls -l env/lib/python2.7/
    $ cd !$
    $ ln -sf ../../../pyenv/lib/python2.7/UserDict.py UserDict.py
    [...repeat until all symbolic links are relative...]
    $ cd ../../../
    
  7. Test

    $ python --version
    Python 2.7.1
    $ source env/bin/activate
    (env)
    $ python --version
    Python 2.7.3
    

Aloha.

Unable to start Genymotion Virtual Device - Virtualbox Host Only Ethernet Adapter Failed to start

In Mac, Open Oracle Virtual Box and Goto VirtualBox -> Preferences -> Network. Select the tab'Host Only Networks' & delete vboxnet0. It will be recreated next time you launch genymotion emulator.

Number prime test in JavaScript

Using Ticked solution Ihor Sakaylyuk

const isPrime = num => {
        for(let i = 2, s = Math.sqrt(num); i <= s; i++)
            if(num % i === 0) return false; 
        return num !== 1 && num !== 0;
}

Gives in console

isPrime( -100 ) true

const isPrime = num => {
  // if not is_number num return false

  if (num < 2) return false

  for(let i = 2, s = Math.sqrt(num); i <= s; i++) {
        if(num % i === 0) return false
  }

  return true
}

Gives in console

isPrime( 1 ) false

isPrime( 100 ) false

isPrime( -100 ) false

First 6 primes ? 2 3 5 7 11 13 ?

isPrime( 1 ) false

isPrime( 2 ) true // Prime 1

isPrime( 3 ) true // Prime 2

isPrime( 4 ) false

isPrime( 5 ) true // Prime 3

isPrime( 6 ) false

isPrime( 7 ) true // Prime 4

isPrime( 8 ) false

isPrime( 9 ) false

isPrime( 10 ) false

isPrime( 11 ) true // Prime 5

isPrime( 12 ) false

isPrime( 13 ) true // Prime 6

Better way to check variable for null or empty string?

Use PHP's empty() function. The following things are considered to be empty

"" (an empty string)
0 (0 as an integer)
0.0 (0 as a float)
"0" (0 as a string)
NULL
FALSE
array() (an empty array)
$var; (a variable declared, but without a value)

For more details check empty function

XPath - Difference between node() and text()

Select the text of all items under produce:

//produce/item/text()

Select all the manager nodes in all departments:

//department/*

How do I get the coordinate position after using jQuery drag and drop?

I was need to save the start position and the end position. this work to me:

    $('.object').draggable({
        stop: function(ev, ui){
            var position = ui.position;
            var originalPosition = ui.originalPosition;
        }
    });

Get real path from URI, Android KitKat new storage access framework

I had the exact same problem. I need the filename so to be able to upload it to a website.

It worked for me, if I changed the intent to PICK. This was tested in AVD for Android 4.4 and in AVD for Android 2.1.

Add permission READ_EXTERNAL_STORAGE :

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

Change the Intent :

Intent i = new Intent(
  Intent.ACTION_PICK,
  android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI
  );
startActivityForResult(i, 66453666);

/* OLD CODE
Intent intent = new Intent();
intent.setType("image/*");
intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(
  Intent.createChooser( intent, "Select Image" ),
  66453666
  );
*/

I did not have to change my code the get the actual path:

// Convert the image URI to the direct file system path of the image file
 public String mf_szGetRealPathFromURI(final Context context, final Uri ac_Uri )
 {
     String result = "";
     boolean isok = false;

     Cursor cursor = null;
      try { 
        String[] proj = { MediaStore.Images.Media.DATA };
        cursor = context.getContentResolver().query(ac_Uri,  proj, null, null, null);
        int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
        cursor.moveToFirst();
        result = cursor.getString(column_index);
        isok = true;
      } finally {
        if (cursor != null) {
          cursor.close();
        }
      }

      return isok ? result : "";
 }

How do I read the source code of shell commands?

Direct links to source for some popular programs in coreutils:

Full list here.

Click event on select option element in chrome

Looking for this on 2018. Click event on option tag, inside a select tag, is not fired on Chrome.

Use change event, and capture the selected option:

$(document).delegate("select", "change", function() {
    //capture the option
    var $target = $("option:selected",$(this));
});

Be aware that $target may be a collection of objects if the select tag is multiple.

How to add an onchange event to a select box via javascript?

Here's another way of attaching the event based on W3C DOM Level 2 Events Specification:

  transport_select.addEventListener(
     'change',
     function() { toggleSelect(this.id); },
     false
  );

Plot multiple lines in one graph

You should bring your data into long (i.e. molten) format to use it with ggplot2:

library("reshape2")
mdf <- melt(mdf, id.vars="Company", value.name="value", variable.name="Year")

And then you have to use aes( ... , group = Company ) to group them:

ggplot(data=mdf, aes(x=Year, y=value, group = Company, colour = Company)) +
    geom_line() +
    geom_point( size=4, shape=21, fill="white")

enter image description here

Does this app use the Advertising Identifier (IDFA)? - AdMob 6.8.0

In app store connect now if we are using ads in our app then we will answer as yes to Does this app use the Advertising Identifier (IDFA)?

further 3 questions will be asked as

enter image description here

if your using just admob then check the first one and leave other two unchecked. Other two options (2nd , 3rd ) will be checked if your using app flyer to show ads. all options are explained with detail here

Applications are expected to have a root view controller at the end of application launch

I had this same problem. Check your main.m. The last argument should be set to the name of the class that implements the UIApplicationDelegate protocol.

retVal = UIApplicationMain(argc, argv, nil, @"AppDelegate");

Using ng-click vs bind within link function of Angular Directive

You should use the controller in the directive and ng-click in the template html, as suggested previous responses. However, if you need to do DOM manipulation upon the event(click), such as on click of the button, you want to change the color of the button or so, then use the Link function and use the element to manipulate the dom.

If all you want to do is show some value on an HTML element or any such non-dom manipulative task, then you may not need a directive, and can directly use the controller.

How to fast get Hardware-ID in C#?

The following approach was inspired by this answer to a related (more general) question.

The approach is to read the MachineGuid value in registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Cryptography. This value is generated during OS installation.

There are few ways around the uniqueness of the Hardware-ID per machine using this approach. One method is editing the registry value, but this would cause complications on the user's machine afterwards. Another method is to clone a drive image which would copy the MachineGuid value.

However, no approach is hack-proof and this will certainly be good enough for normal users. On the plus side, this approach is quick performance-wise and simple to implement.

public string GetMachineGuid()
{
   string location = @"SOFTWARE\Microsoft\Cryptography";
   string name = "MachineGuid";

   using (RegistryKey localMachineX64View = 
       RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64))
   {
       using (RegistryKey rk = localMachineX64View.OpenSubKey(location))
       {
           if (rk == null)
               throw new KeyNotFoundException(
                   string.Format("Key Not Found: {0}", location));

           object machineGuid = rk.GetValue(name);
           if (machineGuid == null)
               throw new IndexOutOfRangeException(
                   string.Format("Index Not Found: {0}", name));

           return machineGuid.ToString();
       }
   }
}

HTML&CSS + Twitter Bootstrap: full page layout or height 100% - Npx

I know it's late in the day but might help someone else!

body,html {
  height: 100%;
}

.contentarea {

 /* 
  * replace 160px with the sum of height of all other divs 
  * inc padding, margins etc 
  */
  min-height: calc(100% - 160px); 
}

Unicode (UTF-8) reading and writing to files in Python

I was trying to parse iCal using Python 2.7.9:

from icalendar import Calendar

But I was getting:

 Traceback (most recent call last):
 File "ical.py", line 92, in parse
    print "{}".format(e[attr])
UnicodeEncodeError: 'ascii' codec can't encode character u'\xe1' in position 7: ordinal not in range(128)

and it was fixed with just:

print "{}".format(e[attr].encode("utf-8"))

(Now it can print liké á böss.)

How to stop flask application without using ctrl-c

If someone else is looking how to stop Flask server inside win32 service - here it is. It's kinda weird combination of several approaches, but it works well. Key ideas:

  1. These is shutdown endpoint which can be used for graceful shutdown. Note: it relies on request.environ.get which is usable only inside web request's context (inside @app.route-ed function)
  2. win32service's SvcStop method uses requests to do HTTP request to the service itself.

myservice_svc.py

import win32service
import win32serviceutil
import win32event
import servicemanager
import time
import traceback
import os

import myservice


class MyServiceSvc(win32serviceutil.ServiceFramework):
    _svc_name_ = "MyServiceSvc"                       # NET START/STOP the service by the following name
    _svc_display_name_ = "Display name"  # this text shows up as the service name in the SCM
    _svc_description_ = "Description" # this text shows up as the description in the SCM

    def __init__(self, args):
        os.chdir(os.path.dirname(myservice.__file__))
        win32serviceutil.ServiceFramework.__init__(self, args)

    def SvcDoRun(self):
        # ... some code skipped
        myservice.start()

    def SvcStop(self):
        """Called when we're being shut down"""
        myservice.stop()
        # tell the SCM we're shutting down
        self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING)
        servicemanager.LogMsg(servicemanager.EVENTLOG_INFORMATION_TYPE,
                              servicemanager.PYS_SERVICE_STOPPED,
                              (self._svc_name_, ''))

if __name__ == '__main__':
    os.chdir(os.path.dirname(myservice.__file__))
    win32serviceutil.HandleCommandLine(MyServiceSvc)

myservice.py

from flask import Flask, request, jsonify

# Workaround - otherwise doesn't work in windows service.
cli = sys.modules['flask.cli']
cli.show_server_banner = lambda *x: None

app = Flask('MyService')

# ... business logic endpoints are skipped.

@app.route("/shutdown", methods=['GET'])
def shutdown():
    shutdown_func = request.environ.get('werkzeug.server.shutdown')
    if shutdown_func is None:
        raise RuntimeError('Not running werkzeug')
    shutdown_func()
    return "Shutting down..."


def start():
    app.run(host='0.0.0.0', threaded=True, port=5001)


def stop():
    import requests
    resp = requests.get('http://localhost:5001/shutdown')

Uploading Images to Server android

Intent photoPickerIntent = new Intent(Intent.ACTION_PICK);
photoPickerIntent.setType("image/*");
startActivityForResult(photoPickerIntent, 1);

ABOVE CODE TO SELECT IMAGE FROM GALLERY

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == 1)
        if (resultCode == Activity.RESULT_OK) {
            Uri selectedImage = data.getData();

            String filePath = getPath(selectedImage);
            String file_extn = filePath.substring(filePath.lastIndexOf(".") + 1);
            image_name_tv.setText(filePath);

            try {
                if (file_extn.equals("img") || file_extn.equals("jpg") || file_extn.equals("jpeg") || file_extn.equals("gif") || file_extn.equals("png")) {
                    //FINE
                } else {
                    //NOT IN REQUIRED FORMAT
                }
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
}

public String getPath(Uri uri) {
    String[] projection = {MediaColumns.DATA};
    Cursor cursor = managedQuery(uri, projection, null, null, null);
    column_index = cursor
            .getColumnIndexOrThrow(MediaColumns.DATA);
    cursor.moveToFirst();
    imagePath = cursor.getString(column_index);

    return cursor.getString(column_index);
}

NOW POST THE DATA USING MULTIPART FORM DATA

HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("LINK TO SERVER");

Multipart FORM DATA

MultipartEntity mpEntity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE);
if (filePath != null) {
    File file = new File(filePath);
    Log.d("EDIT USER PROFILE", "UPLOAD: file length = " + file.length());
    Log.d("EDIT USER PROFILE", "UPLOAD: file exist = " + file.exists());
    mpEntity.addPart("avatar", new FileBody(file, "application/octet"));
}

FINALLY POST DATA TO SERVER

httppost.setEntity(mpEntity);
HttpResponse response = httpclient.execute(httppost);

How do I get just the date when using MSSQL GetDate()?

It's database specific. You haven't specified what database engine you are using.

e.g. in PostgreSQL you do cast(myvalue as date).

How to move an entire div element up x pixels?

you can also do this

margin-top:-30px; 
min-height:40px;

this "help" to stop the div yanking everything up a bit.

SQL: Group by minimum value in one field while selecting distinct rows

I could get to your expected result just by doing this in :

 SELECT id, min(record_date), other_cols 
  FROM mytable
  GROUP BY id

Does this work for you?

Java Command line arguments

Command line arguments are accessible via String[] args parameter of main method.

For first argument you can check args[0]

entire code would look like

public static void main(String[] args) {
    if ("a".equals(args[0])) {
         // do something
    }
}

Understanding repr( ) function in Python

>>> x = 'foo'
>>> x
'foo'

So the name x is attached to 'foo' string. When you call for example repr(x) the interpreter puts 'foo' instead of x and then calls repr('foo').

>>> repr(x)
"'foo'"
>>> x.__repr__()
"'foo'"

repr actually calls a magic method __repr__ of x, which gives the string containing the representation of the value 'foo' assigned to x. So it returns 'foo' inside the string "" resulting in "'foo'". The idea of repr is to give a string which contains a series of symbols which we can type in the interpreter and get the same value which was sent as an argument to repr.

>>> eval("'foo'")
'foo'

When we call eval("'foo'"), it's the same as we type 'foo' in the interpreter. It's as we directly type the contents of the outer string "" in the interpreter.

>>> eval('foo')

Traceback (most recent call last):
  File "<pyshell#5>", line 1, in <module>
    eval('foo')
  File "<string>", line 1, in <module>
NameError: name 'foo' is not defined

If we call eval('foo'), it's the same as we type foo in the interpreter. But there is no foo variable available and an exception is raised.

>>> str(x)
'foo'
>>> x.__str__()
'foo'
>>> 

str is just the string representation of the object (remember, x variable refers to 'foo'), so this function returns string.

>>> str(5)
'5'

String representation of integer 5 is '5'.

>>> str('foo')
'foo'

And string representation of string 'foo' is the same string 'foo'.

Getting the current date in visual Basic 2008

Dim regDate As Date = Date.Now.date

This should fix your problem, though it's 2 years old!

Operator overloading on class templates

You need to say the following (since you befriend a whole template instead of just a specialization of it, in which case you would just need to add a <> after the operator<<):

template<typename T>
friend std::ostream& operator<<(std::ostream& out, const MyClass<T>& classObj);

Actually, there is no need to declare it as a friend unless it accesses private or protected members. Since you just get a warning, it appears your declaration of friendship is not a good idea. If you just want to declare a single specialization of it as a friend, you can do that like shown below, with a forward declaration of the template before your class, so that operator<< is regognized as a template.

// before class definition ...
template <class T>
class MyClass;

// note that this "T" is unrelated to the T of MyClass !
template<typename T>
std::ostream& operator<<(std::ostream& out, const MyClass<T>& classObj);

// in class definition ...
friend std::ostream& operator<< <>(std::ostream& out, const MyClass<T>& classObj);

Both the above and this way declare specializations of it as friends, but the first declares all specializations as friends, while the second only declares the specialization of operator<< as a friend whose T is equal to the T of the class granting friendship.

And in the other case, your declaration looks OK, but note that you cannot += a MyClass<T> to a MyClass<U> when T and U are different type with that declaration (unless you have an implicit conversion between those types). You can make your += a member template

// In MyClass.h
template<typename U>
MyClass<T>& operator+=(const MyClass<U>& classObj);


// In MyClass.cpp
template <class T> template<typename U>
MyClass<T>& MyClass<T>::operator+=(const MyClass<U>& classObj) {
  // ...
  return *this;
}

Jquery- Get the value of first td in table

Install firebug and use console.log instead of alert. Then you will see the exact element your accessing.

How can I add reflection to a C++ application?

Reflection is essentially about what the compiler decided to leave as footprints in the code that the runtime code can query. C++ is famous for not paying for what you don't use; because most people don't use/want reflection, the C++ compiler avoids the cost by not recording anything.

So, C++ doesn't provide reflection, and it isn't easy to "simulate" it yourself as general rule as other answers have noted.

Under "other techniques", if you don't have a language with reflection, get a tool that can extract the information you want at compile time.

Our DMS Software Reengineering Toolkit is generalized compiler technology parameterized by explicit langauge definitions. It has langauge definitions for C, C++, Java, COBOL, PHP, ...

For C, C++, Java and COBOL versions, it provides complete access to parse trees, and symbol table information. That symbol table information includes the kind of data you are likely to want from "reflection". If you goal is to enumerate some set of fields or methods and do something with them, DMS can be used to transform the code according to what you find in the symbol tables in arbitrary ways.

Is it possible to get an Excel document's row count without loading the entire document into memory?

https://pythonhosted.org/pyexcel/iapi/pyexcel.sheets.Sheet.html see : row_range() Utility function to get row range

if you use pyexcel, can call row_range get max rows.

python 3.4 test pass.

How do you close/hide the Android soft keyboard using Java?

there is new API in Android 11 called WindowInsetsController, Apps can get access to a controller from any view, by which we can use hide() and show() method

val controller = view.windowInsetsController

// Show the keyboard (IME)
controller.show(Type.ime())

// Hide the keyboard
controller.hide(Type.ime())

see https://developer.android.com/reference/android/view/WindowInsetsController

No MediaTypeFormatter is available to read an object of type 'String' from content with media type 'text/plain'

Or you can just create your own MediaTypeFormatter. I use this for text/html. If you add text/plain to it, it'll work for you too:

public class TextMediaTypeFormatter : MediaTypeFormatter
{
    public TextMediaTypeFormatter()
    {
        SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/html"));
    }

    public override Task<object> ReadFromStreamAsync(Type type, Stream readStream, HttpContent content, IFormatterLogger formatterLogger)
    {
        return ReadFromStreamAsync(type, readStream, content, formatterLogger, CancellationToken.None);
    }

    public override async Task<object> ReadFromStreamAsync(Type type, Stream readStream, HttpContent content, IFormatterLogger formatterLogger, CancellationToken cancellationToken)
    {
        using (var streamReader = new StreamReader(readStream))
        {
            return await streamReader.ReadToEndAsync();
        }
    }

    public override bool CanReadType(Type type)
    {
        return type == typeof(string);
    }

    public override bool CanWriteType(Type type)
    {
        return false;
    }
}

Finally you have to assign this to the HttpMethodContext.ResponseFormatter property.

How to set top-left alignment for UILabel for iOS application?

In your code

label.text = @"some text";
[label sizeToFit];

Beware that if you use that in table cells or other views that get recycled with different data, you'll need to store the original frame somewhere and reset it before calling sizeToFit.

Keras, How to get the output of each layer?

I wrote this function for myself (in Jupyter) and it was inspired by indraforyou's answer. It will plot all the layer outputs automatically. Your images must have a (x, y, 1) shape where 1 stands for 1 channel. You just call plot_layer_outputs(...) to plot.

%matplotlib inline
import matplotlib.pyplot as plt
from keras import backend as K

def get_layer_outputs():
    test_image = YOUR IMAGE GOES HERE!!!
    outputs    = [layer.output for layer in model.layers]          # all layer outputs
    comp_graph = [K.function([model.input]+ [K.learning_phase()], [output]) for output in outputs]  # evaluation functions

    # Testing
    layer_outputs_list = [op([test_image, 1.]) for op in comp_graph]
    layer_outputs = []

    for layer_output in layer_outputs_list:
        print(layer_output[0][0].shape, end='\n-------------------\n')
        layer_outputs.append(layer_output[0][0])

    return layer_outputs

def plot_layer_outputs(layer_number):    
    layer_outputs = get_layer_outputs()

    x_max = layer_outputs[layer_number].shape[0]
    y_max = layer_outputs[layer_number].shape[1]
    n     = layer_outputs[layer_number].shape[2]

    L = []
    for i in range(n):
        L.append(np.zeros((x_max, y_max)))

    for i in range(n):
        for x in range(x_max):
            for y in range(y_max):
                L[i][x][y] = layer_outputs[layer_number][x][y][i]


    for img in L:
        plt.figure()
        plt.imshow(img, interpolation='nearest')

Download a file from HTTPS using download.file()

You can set global options and try-

options('download.file.method'='curl')
download.file(URL, destfile = "./data/data.csv", method="auto")

For issue refer to link- https://stat.ethz.ch/pipermail/bioconductor/2011-February/037723.html

Converting ISO 8601-compliant String to java.util.Date

I think we should use

DateFormat format = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'")

for Date 2010-01-01T12:00:00Z

NoClassDefFoundError in Java: com/google/common/base/Function

Please include all the jar files of selenium stand-alone and lib folder, then this error will resolved

Where does git config --global get written to?

.gitconfig file location

macOS testing OK

global

# global config
$ cd ~/.gitconfig

# view global config
$ git config --global -l

local

# local config
$ cd .git/config

# view local config
$ git config -l


maybe a bonus for you:Vim or VSCode for edit git config


# open config with Vim

# global config
$ vim ~/.gitconfig

# local config
$ vim .git/config


# open config with VSCode

# global config
$ code ~/.gitconfig

# local config
$ code .git/config