Unix Timestamp Converter

// JavaScript timestamp conversion
function convertUnixTimestamp(timestamp, use12Hour = false) {
  // Create a new Date object (JavaScript uses milliseconds)
  const date = new Date(timestamp * 1000);
  
  // Format options
  const options = {
    year: 'numeric',
    month: 'long',
    day: 'numeric',
    weekday: 'long',
    hour: use12Hour ? 'numeric' : '2-digit',
    minute: '2-digit',
    second: '2-digit',
    hour12: use12Hour
  };
  
  // Convert to string using locale formatting
  return date.toLocaleString(undefined, options);
}

// Example usage
const timestamp = 1609459200; // January 1, 2021 00:00:00 UTC
console.log(convertUnixTimestamp(timestamp, false)); // 24-hour format
console.log(convertUnixTimestamp(timestamp, true));  // 12-hour format

# Python timestamp conversion
import datetime

def convert_unix_timestamp(timestamp, use_12hour=False):
    # Convert Unix timestamp to datetime object
    date = datetime.datetime.fromtimestamp(timestamp)
    
    # Format the date string
    if use_12hour:
        format_string = "%A, %B %d, %Y %I:%M:%S %p"  # 12-hour format with AM/PM
    else:
        format_string = "%A, %B %d, %Y %H:%M:%S"     # 24-hour format
    
    return date.strftime(format_string)

# Example usage
timestamp = 1609459200  # January 1, 2021 00:00:00 UTC
print(convert_unix_timestamp(timestamp, False))  # 24-hour format
print(convert_unix_timestamp(timestamp, True))   # 12-hour format

<?php
// PHP timestamp conversion
function convertUnixTimestamp($timestamp, $use12Hour = false) {
    // Format string
    $formatString = $use12Hour 
        ? 'l, F j, Y g:i:s A'  // 12-hour format with AM/PM
        : 'l, F j, Y H:i:s';   // 24-hour format
    
    // Convert and format the date
    return date($formatString, $timestamp);
}

// Example usage
$timestamp = 1609459200; // January 1, 2021 00:00:00 UTC
echo convertUnixTimestamp($timestamp, false) . "\n"; // 24-hour format
echo convertUnixTimestamp($timestamp, true) . "\n";  // 12-hour format
?>

// Java timestamp conversion
import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;

public class UnixTimestampConverter {
    public static String convertUnixTimestamp(long timestamp, boolean use12Hour) {
        // Convert Unix timestamp to Instant, then to LocalDateTime
        Instant instant = Instant.ofEpochSecond(timestamp);
        LocalDateTime dateTime = LocalDateTime.ofInstant(instant, ZoneId.systemDefault());
        
        // Create formatter based on desired format
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern(
            use12Hour ? "EEEE, MMMM d, yyyy h:mm:ss a" : "EEEE, MMMM d, yyyy HH:mm:ss"
        );
        
        // Format the date
        return dateTime.format(formatter);
    }
    
    public static void main(String[] args) {
        long timestamp = 1609459200; // January 1, 2021 00:00:00 UTC
        System.out.println(convertUnixTimestamp(timestamp, false)); // 24-hour format
        System.out.println(convertUnixTimestamp(timestamp, true));  // 12-hour format
    }
}

// C# timestamp conversion
using System;

class UnixTimestampConverter
{
    public static string ConvertUnixTimestamp(long timestamp, bool use12Hour)
    {
        // Convert Unix timestamp to DateTime
        // Unix timestamp is seconds since 1970-01-01
        DateTime dateTime = DateTimeOffset.FromUnixTimeSeconds(timestamp).DateTime;
        
        // Format string based on 12-hour or 24-hour preference
        string formatString = use12Hour 
            ? "dddd, MMMM d, yyyy h:mm:ss tt"  // 12-hour format with AM/PM
            : "dddd, MMMM d, yyyy HH:mm:ss";   // 24-hour format
        
        // Return formatted date string
        return dateTime.ToString(formatString);
    }
    
    static void Main()
    {
        long timestamp = 1609459200; // January 1, 2021 00:00:00 UTC
        Console.WriteLine(ConvertUnixTimestamp(timestamp, false)); // 24-hour format
        Console.WriteLine(ConvertUnixTimestamp(timestamp, true));  // 12-hour format
    }
}

# Ruby timestamp conversion
require 'time'

def convert_unix_timestamp(timestamp, use_12hour = false)
  # Convert Unix timestamp to Time object
  time = Time.at(timestamp)
  
  # Format based on 12-hour or 24-hour preference
  if use_12hour
    time.strftime("%A, %B %d, %Y %I:%M:%S %p")  # 12-hour format with AM/PM
  else
    time.strftime("%A, %B %d, %Y %H:%M:%S")     # 24-hour format
  end
end

# Example usage
timestamp = 1609459200  # January 1, 2021 00:00:00 UTC
puts convert_unix_timestamp(timestamp, false)  # 24-hour format
puts convert_unix_timestamp(timestamp, true)   # 12-hour format

// Go timestamp conversion
package main

import (
    "fmt"
    "time"
)

func convertUnixTimestamp(timestamp int64, use12Hour bool) string {
    // Convert Unix timestamp to Time
    t := time.Unix(timestamp, 0)
    
    // Format string based on 12-hour or 24-hour preference
    formatString := "Monday, January 2, 2006 "
    if use12Hour {
        formatString += "3:04:05 PM"  // 12-hour format with AM/PM
    } else {
        formatString += "15:04:05"    // 24-hour format
    }
    
    // Return formatted time
    return t.Format(formatString)
}

func main() {
    timestamp := int64(1609459200) // January 1, 2021 00:00:00 UTC
    fmt.Println(convertUnixTimestamp(timestamp, false)) // 24-hour format
    fmt.Println(convertUnixTimestamp(timestamp, true))  // 12-hour format
}

// Swift timestamp conversion
import Foundation

func convertUnixTimestamp(_ timestamp: Int, use12Hour: Bool) -> String {
    // Create Date from Unix timestamp
    let date = Date(timeIntervalSince1970: TimeInterval(timestamp))
    
    // Create DateFormatter
    let formatter = DateFormatter()
    formatter.dateStyle = .full
    
    // Set time style based on 12-hour or 24-hour preference
    if use12Hour {
        formatter.timeStyle = .medium
        formatter.amSymbol = "AM"
        formatter.pmSymbol = "PM"
    } else {
        formatter.timeStyle = .medium
        formatter.dateFormat = formatter.dateFormat?.replacingOccurrences(of: "h:mm:ss a", with: "HH:mm:ss")
    }
    
    // Return formatted date
    return formatter.string(from: date)
}

// Example usage
let timestamp = 1609459200 // January 1, 2021 00:00:00 UTC
print(convertUnixTimestamp(timestamp, use12Hour: false)) // 24-hour format
print(convertUnixTimestamp(timestamp, use12Hour: true))  // 12-hour format

# R timestamp conversion
convert_unix_timestamp <- function(timestamp, use_12hour = FALSE) {
  # Convert Unix timestamp to POSIXct datetime
  date_time <- as.POSIXct(timestamp, origin = "1970-01-01", tz = "UTC")
  
  # Format based on 12-hour or 24-hour preference
  if (use_12hour) {
    format_string <- "%A, %B %d, %Y %I:%M:%S %p"  # 12-hour format with AM/PM
  } else {
    format_string <- "%A, %B %d, %Y %H:%M:%S"     # 24-hour format
  }
  
  # Return formatted date string
  format(date_time, format_string)
}

# Example usage
timestamp <- 1609459200  # January 1, 2021 00:00:00 UTC
cat(convert_unix_timestamp(timestamp, FALSE), "\n")  # 24-hour format
cat(convert_unix_timestamp(timestamp, TRUE), "\n")   # 12-hour format

% MATLAB timestamp conversion
function formattedDate = convertUnixTimestamp(timestamp, use12Hour)
    % Convert Unix timestamp to MATLAB datetime
    date = datetime(timestamp, 'ConvertFrom', 'posixtime');
    
    % Format based on 12-hour or 24-hour preference
    if use12Hour
        formattedDate = datestr(date, 'dddd, mmmm dd, yyyy HH:MM:SS AM');
    else
        formattedDate = datestr(date, 'dddd, mmmm dd, yyyy HH:MM:SS');
    end
end

% Example usage
timestamp = 1609459200;  % January 1, 2021 00:00:00 UTC
disp(convertUnixTimestamp(timestamp, false))  % 24-hour format
disp(convertUnixTimestamp(timestamp, true))   % 12-hour format

' Excel VBA timestamp conversion
Function ConvertUnixTimestamp(timestamp As Long, Optional use12Hour As Boolean = False) As String
    ' Convert Unix timestamp to Excel date/time
    ' Excel dates are days since 1900-01-01, with 1 = 1900-01-01
    ' Unix timestamps are seconds since 1970-01-01
    
    ' First convert to Excel date format
    ' 25569 is the number of days between 1900-01-01 and 1970-01-01
    Dim excelDate As Double
    excelDate = (timestamp / 86400) + 25569
    
    ' Format the date based on 12-hour or 24-hour preference
    If use12Hour Then
        ConvertUnixTimestamp = Format(excelDate, "dddd, mmmm d, yyyy h:mm:ss AM/PM")
    Else
        ConvertUnixTimestamp = Format(excelDate, "dddd, mmmm d, yyyy hh:mm:ss")
    End If
End Function

' Usage in a worksheet:
' =ConvertUnixTimestamp(1609459200, TRUE)  ' 12-hour format
' =ConvertUnixTimestamp(1609459200, FALSE) ' 24-hour format

// JavaScript edge case handling
function safeConvertTimestamp(timestamp, use12Hour = false) {
  // Check if timestamp is valid
  if (timestamp === undefined || timestamp === null || isNaN(timestamp)) {
    return "Invalid timestamp";
  }
  
  // Check for negative timestamps (dates before 1970)
  if (timestamp < 0) {
    // Some browsers might not handle negative timestamps correctly
    // Use a more robust approach for dates before 1970
    const date = new Date(timestamp * 1000);
    if (isNaN(date.getTime())) {
      return "Invalid date (before 1970)";
    }
  }
  
  // Check for Y2K38 problem (for 32-bit systems)
  const maxInt32 = 2147483647; // Maximum value for 32-bit signed integer
  if (timestamp > maxInt32) {
    // Consider using BigInt for very large timestamps in modern JavaScript
    console.warn("Timestamp exceeds 32-bit integer limit (Y2K38 issue)");
  }
  
  // Proceed with normal conversion
  try {
    const date = new Date(timestamp * 1000);
    const options = {
      year: 'numeric',
      month: 'long',
      day: 'numeric',
      weekday: 'long',
      hour: use12Hour ? 'numeric' : '2-digit',
      minute: '2-digit',
      second: '2-digit',
      hour12: use12Hour
    };
    return date.toLocaleString(undefined, options);
  } catch (error) {
    return "Error converting timestamp: " + error.message;
  }
}