Numworks Python: Days Between Days Without Converting to Julian Dates

Numworks Python: Days Between Days Without Converting to Julian Dates

Introduction

The script daysbtwn.py find the number days between two days given the month and year. The program is designed to find the dates, not including the last date (to match most financial calculators and spreadsheets), within one calendar year. The program will ask if February 29 is included.

Numworks Python Code: daysbtwn.py

from math import *

# days between dates within a year

# no conversion to julian approach

# store basic calendar

# 0th is 0 to match the months

cal=[0,31,28,31,30,31,30,31,31,30,31,30,31,31,28,31,30,31,30,31,31,30,31,30,31]

# ask for dates

m1=int(input("Month 1? "))

d1=int(input("Day 1? "))

m2=int(input("Month 2? "))

d2=int(input("Day 2? "))

# leap year question

l=0

l=int(input("Include Feb. 29?\nYES=1, NO=0: "))

# sum

if m1==m2:

  s=d2-d1

  if s<=0:

    s+=365+l  

else:

  if m2<m1:

    m2+=12

  s=cal[m1]-d1

  s+=sum(cal[m1+1:m2])

  s+=d2+l

print("DAYS = ",s)

The code has the math module, which can be used with any calculator with Python or the computer version.

Examples

March 14 – March 13 (of next year)

Month 1? 3, Day 1? 14

Month 2? 3, Day 2? 13

Include Feb. 29? 0

Number of Days: 364

March 14 – March 14 (of next year)

Month 1? 3, Day 1? 14

Month 2? 3, Day 2? 14

Include Feb. 29? 0

Number of Days: 365

March 14 – March 15 (of the same year)

Month 1? 3, Day 1? 14

Month 2? 3, Day 2? 15

Include Feb. 29? 0

Number of Days: 1

January 1 – December 31 (of the same year – leap year)

Month 1? 1, Day 1? 1

Month 2? 12, Day 2? 31

Include Feb. 29? 1

Number of Days: 365

In the U.S., wishing you a safe, sane, and Happy Thanksgiving.

Eddie

All original content copyright, © 2011-2025. Edward Shore. Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited. This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.

Intensity/Illumination, Days Since Jan. 1, Derivatives: HP 20S and 21S

Intensity/Illumination, Days Since Jan. 1, Derivatives: HP 20S and 21S

Table of contents

1.  Intensity and Illumination
2.  Days Since January 1
3.  Numerical Derivative

Disclaimer: I believe the key codes for the programs in this blog entry are the all the same even though the HP 20S and HP 21S have slightly different codes.  Format:   Step  Key: Key Code.  I took turns programming the HP 20S and HP 21S.

1.  Intensity and Illumination

The follow equation relates the luminous intensity (measured in candelas, cd) and illuminance (measured in lux) of a light source.  The equation assumes the light source radiates a spherical matter.

E = I / R^2

E = illuminance
I = luminous intensity
R = radius of the sphere's light (meters)

LBL A:  Solve for E
LBL B:  Solve for I
LBL C:  Solve for R

Registers:
R0 = E
R1 = I
R2 = R

Store the following values in the register and execute the appropriate label.

Program:

01  LBL A:  61,41,A
02 RCL 1:  22, 1
03 ÷:  45
04 RCL 2:  22, 2
05 x^2:  51, 11
06 =: 74
07 STO 0:  21, 0
08 R/S:  26
09 LBL B:  61,41,B
10  RCL 0: 22,0
11  *:  55
12  RCL 2: 22,2
13  x^2:  51,11
14  =:  74
15  STO 1: 21, 1
16  R/S:  26
17  LBL C: 61,41,C
18  RCL 1: 22,1
19 ÷: 45
20 RCL 0: 22,0
21  =:  74
22 √:  11
23 STO 2: 21, 2
24 R/S:  26

Example 1:
R1 = I = 400, R2 = R = 2.
Solve for E,  XEQ A returns 100

Example 2:
R0 = E = 180, R2 = R = 3
Solve for I, XEQ B returns 1620

Example 3:
R1 = I =420, R0 = E = 195
Solve for R, XEQ C returns 1.467598771

2.  Days Since January 1

Calculate the number of days since January 1.  For more information, please see:  http://edspi31415.blogspot.com/2019/03/ti-84-plus-and-hp-41c-number-of-days.html

Input:
R1:  day
R2: month
R3: 0 if we are working in a non-leap year, 1 if we are working in a leap year

Output:
R4:  number of days since January 1

Program:

01 LBL A: 61,41,A
02 RCL 1:  22,1
03 STO 4: 21, 4
04 3:  3
05 5:  5
06 STO - 4:  21,65,4
07 RCL 2: 22,2
08  INPUT:  31
09  2:  2
10  x ≤ y?:  61,42
11  GTO 2:  51,41,2
12  RCL 2: 22,2
13  *:  55
14  3:  3
15  0:  0
16  . : 73
17 6:  6
18  +:  75
19  1:  1
20  .  : 73
21  6:  6
22  =:  74
23  IP:  51, 45
24  STO + 4:  21,75,4
25  RCL 3:  22,3
26  STO + 4:  21,75,4
27  RCL 4: 22,4
28  RTN:  61, 26
29  LBL 2:  61,41,2
30  RCL 2:  22,2
31   *:  55
32  3:  3
33  0:  0
34  .  : 73
35  6:  6
36  +:  75
37  3:  3
38  6:  6
39  8:  8
40:  .  : 73
41  8:  8
42 =: 74
43  IP:  51,45
44  STO + 4:  21,75,4
45  3:  3
46  6:  6
47  5:  5
48  STO - 4:  21,65,4
49  RCL 4:  22,4
50  RTN:  61,26

Example 1:
1/1/2019 - 5/7/2019  (non-leap year)
R1:  7,  R2:  5,  R3:  0
Result:  R4 = 126

Example 2:
1/1/2020 - 11/14/2020  (leap year)
R1:  14,  R2:  11, R3:  1
Result:  R4 = 318

3.  Numerical Derivative

f'(x0) ≈ ( f(x0 + h) - f(x0 - h) ) / ( 2*h )

x = point
h = small change of x, example h = 0.0001

LBL A:  Main Progam
LBL F:  f(X), where R0 acts as X

Input variables:
R1 = h
R2 = point x0

Used variables:
R0 = x   (use R0 for f(x), LBL F)

Calculated Variables:
R3 = f'(x)

Radians mode will be set.

Program:

01  LBL A:  61,41A
02  RAD:  61,24
03  RCL 2:  22,2
04  +:  75
05  RCL 1:  22, 1
06  =:  74
07  STO 0:  21,0
08 XEQ F:  41,F
09  STO 3:  21, 3
10  RCL 2: 22,2
11 -:  65
12 RCL 1: 22,1
13 =:  74
14 STO 0: 21,0
15 XEQ F:  41,F
16 STO - 3:  21,65,3
17 2:  2
18 STO ÷ 3:  21,45,3
19  RCL 1:  22,1
20 STO ÷ 3: 21,45,3
21  RCL 3:  22,3
22 R/S:  26
23 LBL F:  61,41,F
...
xx  RTN:  61,26  (end f(X) with RTN)

Example:  e^x * sin x

LBL F
RCL 0
e^x
*
RCL 0
SIN 
= 
RTN

R1 = 0.0001
R2 = x0 = 0.03
Result:  1.060899867

R1 = 0.0001
R2 = x0 = 1.47
Result:  4.7648049


Note:  I am going on vacation this week and I have jury duty in June. So far, I have blog entries scheduled to be posted throughout June 22.  I plan to have a weekly post every Saturday in June.  - E

Eddie

All original content copyright, © 2011-2019.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.

TI-84 Plus and HP 41C: Number of Days After January 1

TI-84 Plus and HP 41C:  Number of Days After January 1

Introduction

The program DATENO calculates the number of days from January 1.  The program prompts whether we are working in a leap year or not. 

With D = Day and M = Month, the days between January 1 and any other date within the calendar year is:

If M = 1 and M = 2 Then
DATE# = int(30.6 * M + 368.8) + D - 400

Otherwise,
DATE# = int(30.6 * M + 1.6) +D - 35  (non-leap year)
DATE# = int(30.6 * M + 1.6) + D - 34  (leap year)

TI-84 Plus Program: DATENO

"DAYS AFTER JANUARY 1"
"2019-03-07 EWS"
Input "MONTH: ",M
Input "DAY: ",D
Disp "0:NO, 1:YES"
Input "LEAP YEAR? ",L
If M≥3
Then
int(30.6*M+1.6)+D-35+L→T
Else
int(30.6*M+368.8)+D-400→T
End
Disp T

HP 41C/DM 41L Program:  DATENO

(^T:  beginning of an alpha string)

01 LBL^T DATENO
02 ^T MONTH
03 PROMPT
04 STO 01
05 ^T DAY?
06 PROMPT
07 STO 02
08 ^T LEAP? N=0,L=1
09 PROMPT
10 STO 03
11 RCL 01
12 3
13 X<=Y?
14 GTO 00
15 30.6
16 RCL 01
17 *
18 368.8
19 +
20 INT
21 RCL 02
22 +
23 400
24 -
25 GTO 01
26 LBL 00
27 RCL 01
28 30.6
29 *
30 1.6
31 +
32 INT
33 RCL 02
34 + 
35 35
36 - 
37 RCL 03
38 + 
39 LBL 01
40 STO 04
41 END

Examples

Days between January 1 and February 16  (M = 2, D = 16):  46

Days between January 1 and October 1 (M = 10, D = 1):
(Non-leap year):  273
(Leap year): 274

Eddie

All original content copyright, © 2011-2019.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.