使用 gnuplot 对数据进行排序

Question

有时可能需要对数据进行排序。不幸的是，gnuplot（据我所知）不提供这种可能性。当然，你可以使用awk、Perl、Python等外部工具。但是，为了最大限度的平台独立性，避免安装额外的程序和相关的复杂性，也出于好奇，我很感兴趣gnuplot是否可以排序尽管如此。如果您对改进、限制提出意见，我将不胜感激。

有人知道如何仅使用 gnuplot 对字母数字数据进行排序吗？

### Sorting with gnuplot
reset session

# generate some random example data
N = 10
set samples N
RandomNo(n) = sprintf("%.02f",rand(0)*n)
set table $Data
    plot '+' u (RandomNo(10)):(RandomNo(10)):(RandomNo(10)) w table
unset table
print $Data

# Settings for sorting
ColNo = 2   # ColumnNo for sorting
stats $Data nooutput      # get the number of rows if data is from file
RowCount = STATS_records  # with the example data above, of course RowCount=N

# create the sortkey and put it into an array
array SortKey[RowCount]
set table $Dummy
    plot $Data u (SortKey[[=10=]+1] = sprintf("%.06f%02d",column(ColNo),[=10=]+1)) w table
unset table
# print $Dummy

# get lines as whole into array
set datafile separator "\n"
array DataSeq[RowCount]
set table $Dummy2
    plot $Data u (SortKey[[=10=]+1]):(DataSeq[[=10=]+1] = stringcolumn(1)) with table
unset table
print $Dummy2
set datafile separator whitespace

# do the actual sorting with 'smooth unique'
set table $Dummy3
    plot $Dummy2 u 1:0 smooth unique
unset table
# print $Dummy3

# extract the sorted sortkeys
set table $Dummy4
    plot $Dummy3 u (SortKey[[=10=]+1]=) with table
unset table
# print $Dummy4

# create the table with sorted lines
set table $DataSorted
    plot $Data u (DataSeq[SortKey[[=10=]+1]+1]) with table
unset table
print $DataSorted
### end of code

第一个数据块未排序数据
带有排序键的第二个数据块
第三个数据块按第二列排序数据

输出：

 5.24    6.68    3.09   
 1.64    1.27    9.82   
 6.44    9.23    7.03   
 8.14    8.87    3.82   
 4.27    5.98    0.93   
 7.96    3.64    6.15   
 6.21    6.28    6.17   
 1.52    3.17    3.58   
 4.24    2.16    8.99   
 8.73    6.54    1.13   

 6.68000001      5.24    6.68    3.09
 1.27000002      1.64    1.27    9.82
 9.23000003      6.44    9.23    7.03
 8.87000004      8.14    8.87    3.82
 5.98000005      4.27    5.98    0.93
 3.64000006      7.96    3.64    6.15
 6.28000007      6.21    6.28    6.17
 3.17000008      1.52    3.17    3.58
 2.16000009      4.24    2.16    8.99
 6.54000010      8.73    6.54    1.13

 1.64    1.27    9.82
 4.24    2.16    8.99
 1.52    3.17    3.58
 7.96    3.64    6.15
 4.27    5.98    0.93
 6.21    6.28    6.17
 8.73    6.54    1.13
 5.24    6.68    3.09
 8.14    8.87    3.82
 6.44    9.23    7.03

Answer 1

出于好奇，我想知道是否可以仅使用 gnuplot 代码实现字母数字排序。这避免了对外部工具的需要，并确保了最大的平台兼容性。我还没有听说过可以辅助 gnuplot 并且在 Windows and Linux and 下工作的外部工具苹果系统。我很乐意接受有关错误、简化、改进、性能比较和限制的评论和建议。

对于字母数字排序，第一阶段是字母数字字符串比较，据我所知gnuplot中不直接存在。所以，第一部分Compare.plt是关于字符串的比较。

### compare function for strings 
# Compare.plt
# function cmp(a,b,cs) returns a<b:-1, a==b:0, a>b:+1
# cs=0: case-insensitive, cs=1: case-sensitive
reset session

ASCII =  ' !"' . "#$%&'()*+,-./0123456789:;<=>?@".\
         "ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_\`".\
         "abcdefghijklmnopqrstuvwxyz{|}~"

ord(c) = strstrt(ASCII,c)>0 ? strstrt(ASCII,c)+31 : 0

# comparing char: case-sensitive
cmpcharcs(c1,c2) = sgn(ord(c1)-ord(c2))

# comparing char: case-insentitive
cmpcharci(c1,c2) = sgn(( cmpcharci_o1=ord(c1), ((cmpcharci_o1>96) && (cmpcharci_o1<123)) ?\
    cmpcharci_o1-32 : cmpcharci_o1) - \
    ( cmpcharci_o2=ord(c2), ((cmpcharci_o2>96) && (cmpcharci_o2<123)) ?\
    cmpcharci_o2-32 : cmpcharci_o2) )

# function cmp returns a<b:-1, a==b:0, a>b:+1
# cs=0: case-insensitive, cs=1: case-sensitive
cmp(a,b,cs) = ((cmp_r=0, cmp_flag=0, cmp_maxlen=strlen(a)>strlen(b) ? strlen(a) : strlen(b)),\
    (sum[cmp_i=1:cmp_maxlen] \
      ((cmp_flag==0 && (cmp_c1 = substr(a,cmp_i,cmp_i), cmp_c2 = substr(b,cmp_i,cmp_i), \
        (cmp_r = (cs==0 ?  cmpcharci(cmp_c1,cmp_c2) : cmpcharcs(cmp_c1,cmp_c2) ) )!=0 ? \
        (cmp_flag=1, cmp_r) : 0)), 1 )), cmp_r)

cmpsymb(a,b,cs) = (cmpsymb_r = cmp(a,b,cs))<0 ? "<" : cmpsymb_r>0 ? ">" : "="
### end of code

示例：

### example compare strings
load "Compare.plt"

a="Alligator"
b="Tiger"
print sprintf("% 2d: % 9s% 2s% 6s", cmp(a,b,0), a, cmpsymb(a,b,0), b)

a="Tiger"
print sprintf("% 2d: % 9s% 2s% 6s", cmp(a,b,0), a, cmpsymb(a,b,0), b)

a="Zebra"
print sprintf("% 2d: % 9s% 2s% 6s", cmp(a,b,0), a, cmpsymb(a,b,0), b)
### end of code

结果：

-1: Alligator < Tiger
 0:     Tiger = Tiger
 1:     Zebra > Tiger

第二部分利用比较进行排序

### alpha-numerical sort with gnuplot
reset session
load "Compare.plt"

$Data <<EOD
1   0.123   Orange
2   0.456   Apple
3   0.789   Peach
4   0.987   Pineapple
5   0.654   Banana
6   0.321   Raspberry
7   0.111   Lemon
EOD

stats $Data u 0 nooutput
RowCount = STATS_records
ColSort = 3

array Key[RowCount]
array Index[RowCount]

set table $Dummy
    plot $Data u (Key[[=13=]+1]=stringcolumn(ColSort),Index[[=13=]+1]=[=13=]+1) w table
unset table

# Bubblesort
do for [n=RowCount:2:-1] {
    do for [i=1:n-1] {
        if ( cmp(Key[i],Key[i+1],0) > 0) { 
            tmp=Key[i]; Key[i]=Key[i+1]; Key[i+1]=tmp
            tmp2=Index[i]; Index[i]=Index[i+1]; Index[i+1]=tmp2
        }
    }
}

set datafile separator "\n"
set table $Dummy    # and reuse Key-array
    plot $Data u (Key[[=13=]+1]=stringcolumn(1)) with table
unset table
set datafile separator whitespace

set table $DataSorted
    plot $Data u (Key[Index[[=13=]+1]]) with table
unset table

print $DataSorted
set grid xtics,ytics
plot [-0.5:RowCount-0.5][0:1.1] $DataSorted u 0:2:xtic(3) w lp lt 7 lc rgb "red"
### end of code

输入：

1   0.123   Orange
2   0.456   Apple
3   0.789   Peach
4   0.987   Pineapple
5   0.654   Banana
6   0.321   Raspberry
7   0.111   Lemon

输出：

 2      0.456   Apple   
 5      0.654   Banana  
 7      0.111   Lemon   
 1      0.123   Orange  
 3      0.789   Peach   
 4      0.987   Pineapple       
 6      0.321   Raspberry

和输出图：

使用 gnuplot 对数据进行排序

Sorting data with gnuplot

sorting

gnuplot

columnsorting