Creating 2 dimesional array with user input and find sum of specific columns

» java » Creating 2 dimesional array with user input and find sum of specific columns

By : homerican

Date : January 11 2021, 05:14 PM

fixed the issue. Will look into that further Please assist with my code. There must be 3 rows and 4 columns in the array. The user must be able to enter doubles for the first 2 columns. Then I should be able to calculate the sum of each column in the array. , You now need to add the array values by column. It can be as easy as:

code :

private void printSumForColumn(int[][] array, int col)
{
  int sum = 0;
  for (int i = 0; i < row; i++)
  {
    sum += array[i][col];
  }
  System.out.println("The sum of column " + col + " is " + sum);
}

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Creating an object of specific type based on user input

By : Rai Moreira

Date : March 29 2020, 07:55 AM

wish of those help For specific size, if you compute a single index, you may dispatch at runtime to the correct compile time function:

code :

template <std::size_t N>
std::unique_ptr<Base> make_thing3()
{
    constexpr Enum a2 = Enum(N % NumEnums);
    constexpr Enum a1 = Enum((N / NumEnums) % NumEnums);
    constexpr Enum a0 = Enum((N / NumEnums / NumEnums) % NumEnums);
    return std::make_unique<Thing<a0, a1, a2>>();
}

template <std::size_t... Is>
std::unique_ptr<Base> make_thing3(std::size_t index, std::index_sequence<Is...>)
{
    using maker = std::unique_ptr<Base>();
    maker* fs[] = {&make_thing3<Is>...};

    return fs[index]();
}

std::unique_ptr<Base> make_thing3(const std::array<Enum, 3u>& a)
{
    std::size_t index = 0;
    for (Enum e : a) {
        index *= NumEnums;
        index += e;
    }
    constexpr std::size_t total = NumEnums * NumEnums * NumEnums;

    return make_thing3(index, std::make_index_sequence<total>{});
}

Search multi-dimesional array and return specific value

By : Neetu M

Date : March 29 2020, 07:55 AM

I wish did fix the issue. Hard to phrase my question, but here goes. I've got a string like so: "13,4,3|65,1,1|27,3,2". The first value of each sub group (ex. 13,4,3) is an id from a row in a database table, and the other numbers are values I use to do other things. , Run one more foreach loop like this:

code :

$value_to_search = 27;
foreach($return_2d_array as $array){ 
    if($array[0] == $value_to_search){ 
        echo $array[1];  // will give 3
        break; 
    } 
}

C#: Creating a string array from user input, then if it can't be parsed into int array, retrying the input

By : yangjw

Date : March 29 2020, 07:55 AM

With these it helps First of all, make the user experience as good as possible. Inputing a matrix all at once can be error prone, make the user's life easier and take it step by step.
Second, make small methods that perform simple tasks; they are easier to reason about, easier to write, easier to debug and easier to modify if new requirements come along. Don't make methods do too much, it will only buy you headaches and more debugging hours than necessary. If you are learning, don't worry if it seems you are breaking down to seemingly absurdly simple tasks, you wont regret it. Always remember that the most complicated problems you can imagine are always solved solving smaller and easier ones.

code :

private static int GetIntegerFromUser(string prompt)
{
    int value;
    Console.Write($"{prompt}: ");

    while (!int.TryParse(Console.ReadLine(), out value))
    {
        Console.WriteLine("That is not a valid value. Please try again.");
        Console.Write($"{prompt}: ");
    }

    return value;
}

private static (int Rows, int Columns) GetMatrixSize()
{
    var rows = GetIntegerFromUser("Please enter number of rows");
    var columns = GetIntegerFromUser("Please enter number of columns");
    return (rows, columns);
}

private static int[,] GetMatrixValues(int rows, int columns)
{
    var matrix = new int[rows, columns];

    for (var row = 0; row < rows; row++)
    {
        for (var column = 0; column < columns; column++)
        {
            matrix[row, column] =
               GetIntegerFromUser($"Enter matrix value [{row}, {column}]");
        }
    }
}

public static int[,] GetMatrixFromUser()
{
    var size = GetMatrixSize();
    return GetMatrixValues(size.Rows, size.Columns);
}

private static bool IsInRange(int value, 
                              int lowerInclusiveBound,
                              int upperExclusiveBound,
                              string messageOnFailedValidation)
{
    if (value >= lowerInclusiveBound &&
        value < upperExclusiveBound)
        return true;

    Console.WriteLine(messageOnFailedValidation);
    return false;
}

private static (int Rows, int Columns) GetMatrixSize()
{
    int rows, columns;

    do
    {
        rows = GetIntegerFromUser("Please enter number of rows");
        columns = GetIntegerFromUser("Please enter number of columns");
    } while (!IsInRange(rows,
                        1,
                        int.MaxValue,
                        "Number of rows must be equal or greater than one.") |
             !IsInRange(columns,
                        1,
                        int.MaxValue,
                        "Number of columns must be equal or greater than one."));

    return (rows, columns);
}

private static int[,] GetMatrixValues(int rows, int columns)
{
    Debug.Assert(rows > 0 && columns > 0);
    var matrix = ...
}

private static bool IsInRange(int value, 
                              int lowerInclusiveBound,
                              int upperExclusiveBound,
                              string messageOnFailedValidation)
{  
    Debug.Assert(upperExclusiveBound > lowerInclusiveBound);

    if ...
}

plotting specific columns based on user input

By : brainvat

Date : March 29 2020, 07:55 AM

Hope this helps I'm having trouble figuring out your example code, one thing that could help to solve the problem is to re-create a simpler version of what you're trying to do, without hard-to-deal-with column names.

code :

import random
import pandas as pd

data={
    'a': [random.randint(0, 50) for i in range(4)],
    'b': [random.randint(0, 50) for i in range(4)],
    'c': [random.randint(0, 50) for i in range(4)]
}

df = pd.DataFrame(data)
df.index = df.index.rename('Ind')

user_input = 'b'

if user_input in df.columns:
    ax = df[user_input].plot(x='Ind', kind='bar')