怎么计算两个日期间的天数

guang

有没有现成的方法?
日期的格式为YYMMDD
谢谢!~
或者计算一个日期距当前日期的天数?

guang

这是我写的函数..
[PHP]
interdays(){
   local s1 s2 s3
   s1=`date +%s -d$1`
   s2=`date +%s -d$2`
   if [ $s1 -gt $s2 ]
   then
        s3=$(($s1 - $s2))
   else
        s3=$(($s2 - $s1))
   fi
   return $((s3 / (60 * 60 * 24)))
}
[/PHP]

kiron

用cal来处理吧.,你上面的代码要是出现跨月份的就很难计算了.

troll

abs-guide中有一个计算两个日期中天数的例子，但它的格式是mm/dd/yyyy：

1. #!/bin/bash
   
2. # days-between.sh:    Number of days between two dates.
   
3. # Usage: ./days-between.sh [M]M/[D]D/YYYY [M]M/[D]D/YYYY
   
4. #
   
5. # Note: Script modified to account for changes in Bash 2.05b
   
6. #+      that closed the loophole permitting large negative
   
7. #+      integer return values.
   
8. 
   
9. ARGS=2                # Two command line parameters expected.
   
10. E_PARAM_ERR=65        # Param error.
    
11. 
    
12. REFYR=1600            # Reference year.
    
13. CENTURY=100
    
14. DIY=365
    
15. ADJ_DIY=367           # Adjusted for leap year + fraction.
    
16. MIY=12
    
17. DIM=31
    
18. LEAPCYCLE=4
    
19. 
    
20. MAXRETVAL=255         #  Largest permissable
    
21.                       #+ positive return value from a function.
    
22. 
    
23. diff=                 # Declare global variable for date difference.
    
24. value=                # Declare global variable for absolute value.
    
25. day=                  # Declare globals for day, month, year.
    
26. month=
    
27. year=
    
28. 
    
29. 
    
30. Param_Error ()        # Command line parameters wrong.
    
31. {
    
32.   echo "Usage: `basename $0` [M]M/[D]D/YYYY [M]M/[D]D/YYYY"
    
33.   echo "       (date must be after 1/3/1600)"
    
34.   exit $E_PARAM_ERR
    
35. }  
    
36. 
    
37. 
    
38. Parse_Date ()                 # Parse date from command line params.
    
39. {
    
40.   month=${1%%/**}
    
41.   dm=${1%/**}                 # Day and month.
    
42.   day=${dm#*/}
    
43.   let "year = `basename $1`"  # Not a filename, but works just the same.
    
44. }  
    
45. 
    
46. 
    
47. check_date ()                 # Checks for invalid date(s) passed.
    
48. {
    
49.   [ "$day" -gt "$DIM" ] || [ "$month" -gt "$MIY" ] || [ "$year" -lt "$REFYR" ] && Param_Error
    
50.   # Exit script on bad value(s).
    
51.   # Uses "or-list / and-list".
    
52.   #
    
53.   # Exercise: Implement more rigorous date checking.
    
54. }
    
55. 
    
56. 
    
57. strip_leading_zero () #  Better to strip possible leading zero(s)
    
58. {                     #+ from day and/or month
    
59.   return ${1#0}       #+ since otherwise Bash will interpret them
    
60. }                     #+ as octal values (POSIX.2, sect 2.9.2.1).
    
61. 
    
62. 
    
63. day_index ()          # Gauss' Formula:
    
64. {                     # Days from Jan. 3, 1600 to date passed as param.
    
65. 
    
66.   day=$1
    
67.   month=$2
    
68.   year=$3
    
69. 
    
70.   let "month = $month - 2"
    
71.   if [ "$month" -le 0 ]
    
72.   then
    
73.     let "month += 12"
    
74.     let "year -= 1"
    
75.   fi  
    
76. 
    
77.   let "year -= $REFYR"
    
78.   let "indexyr = $year / $CENTURY"
    
79. 
    
80. 
    
81.   let "Days = $DIY*$year + $year/$LEAPCYCLE - $indexyr + $indexyr/$LEAPCYCLE + $ADJ_DIY*$month/$MIY + $day - $DIM"
    
82.   #  For an in-depth explanation of this algorithm, see
    
83.   #+ http://home.t-online.de/home/berndt.schwerdtfeger/cal.htm
    
84. 
    
85. 
    
86.   echo $Days
    
87. 
    
88. }  
    
89. 
    
90. 
    
91. calculate_difference ()            # Difference between to day indices.
    
92. {
    
93.   let "diff = $1 - $2"             # Global variable.
    
94. }  
    
95. 
    
96. 
    
97. abs ()                             #  Absolute value
    
98. {                                  #  Uses global "value" variable.
    
99.   if [ "$1" -lt 0 ]                #  If negative
    
100.   then                             #+ then
     
101.     let "value = 0 - $1"           #+ change sign,
     
102.   else                             #+ else
     
103.     let "value = $1"               #+ leave it alone.
     
104.   fi
     
105. }
     
106. 
     
107. 
     
108. 
     
109. if [ $# -ne "$ARGS" ]              # Require two command line params.
     
110. then
     
111.   Param_Error
     
112. fi  
     
113. 
     
114. Parse_Date $1
     
115. check_date $day $month $year       #  See if valid date.
     
116. 
     
117. strip_leading_zero $day            #  Remove any leading zeroes
     
118. day=$?                             #+ on day and/or month.
     
119. strip_leading_zero $month
     
120. month=$?
     
121. 
     
122. let "date1 = `day_index $day $month $year`"
     
123. 
     
124. 
     
125. Parse_Date $2
     
126. check_date $day $month $year
     
127. 
     
128. strip_leading_zero $day
     
129. day=$?
     
130. strip_leading_zero $month
     
131. month=$?
     
132. 
     
133. date2=$(day_index $day $month $year) # Command substitution.
     
134. 
     
135. 
     
136. calculate_difference $date1 $date2
     
137. 
     
138. abs $diff                            # Make sure it's positive.
     
139. diff=$value
     
140. 
     
141. echo $diff
     
142. 
     
143. exit 0
     
144. #  Compare this script with
     
145. #+ the implementation of Gauss' Formula in a C program at:
     
146. #+    http://buschencrew.hypermart.net/software/datedif

复制代码

以下来自comp.unix.shell

在cus的fag上看到过一个date2julian()函数，把公历日期转换儒略日计数（Julian Day Count），然后就可以方便地计算出两个日期间相差的天数了
这个应该比较符合楼主需求

1. # Date calculations using Korn shell (ksh88)
   
2. # Tapani Tarvainen July 1998, May 2000
   
3. # This code is in the public domain.
   
4. # Julian Day Number from calendar date
   
5. date2julian()   #  day month year
   
6. {
   
7.   typeset -i day month year tmpmonth tmpyear
   
8.   day=$1;  month=$2;  year=$3
   
9.   ((tmpmonth = 12 * year + month - 3))
   
10.   ((tmpyear = tmpmonth / 12))
    
11.   print $(( (734 * tmpmonth + 15) / 24 -  2 * tmpyear + \
    
12.     tmpyear/4 - tmpyear/100 + tmpyear/400 + day + 1721119 ))
    
13. }

复制代码

处理各种不同的日期格式。

1. 
   
2. #!/bin/ksh
   
3. ###########################################################################
   
4. # Date calculations using Korn shell (ksh88)
   
5. # Tapani Tarvainen July 1998, May 2000
   
6. # This code is in the public domain.
   
7. # Julian Day Number from calendar date
   
8. date2julian()   #  day month year
   
9. {
   
10.   typeset -i day month year tmpmonth tmpyear
    
11.   day=$1;  month=$2;  year=$3
    
12.   ((tmpmonth = 12 * year + month - 3))
    
13.   ((tmpyear = tmpmonth / 12))
    
14.   print $(( (734 * tmpmonth + 15) / 24 -  2 * tmpyear + \
    
15.     tmpyear/4 - tmpyear/100 + tmpyear/400 + day + 1721119 ))
    
16. 
    
17. }
    
18. 
    
19. ###
    
20. # Matt's Added formatting
    
21. ###
    
22. 
    
23. # Store input dates
    
24. date1=$1
    
25. date2=$2
    
26. 
    
27. # Get the dates into their respective fields.  Uncomment the format of
    
28. # date input being used.
    
29. 
    
30. # YYYYMMDD
    
31. year1=${date1%????}; mmdd1=${date1#????}; month1=${mmdd1%??}; day1=${mmdd1#??}
    
32. year2=${date2%????}; mmdd2=${date2#????}; month2=${mmdd2%??}; day2=${mmdd2#??}
    
33. 
    
34. # YYYY/MM/DD  or YYYY/M/D
    
35. #print $date1 |IFS=/ read year1 month1 day1
    
36. #print $date2 |IFS=/ read year2 month2 day2
    
37. 
    
38. # MM/DD/YY    or M/D/YYYY
    
39. #print $date1 |IFS=/ read month1 year1 day1
    
40. #print $date2 |IFS=/ read month2 year2 day2
    
41. 
    
42. # Calculate and print the difference between dates (date2 - date1)
    
43. print -- "$(($(date2julian $day2 $month2 $year2) - $(date2julian $day1 \
    
44. $month1 $year1)))"

复制代码

BASH需要做一些相应修改。

guang

Post by kiron
用cal来处理吧.,你上面的代码要是出现跨月份的就很难计算了.

这个是为什么呢? 我把时间转换成距格林威治的秒数了,为什么会有跨月份的问题?

kiron

Post by guang
这个是为什么呢? 我把时间转换成距格林威治的秒数了,为什么会有跨月份的问题?

Sorry,我没试过就乱下结论,不好意思 :sorry

upandup

看起来没什么问题。

guang

to : kiron
你说用cal 怎么计算?

kiron

Post by guang
to : kiron
你说用cal 怎么计算?

cal可以打印出儒略日,只需找到你指定的天数之间的儒略日,相减即可.

huhuegg

用两个日期的日期戳的差/86400