Reputation: 37
I have a data file which content two columns. One of them have periodic variation of whom the max and min are different in each period :
a 3
b 4
c 5
d 4
e 3
f 2
g 1
h 2
i 3
j 4
k 5
l 6
m 5
n 4
o 3
p 2
q 1
r 0
s 1
t 2
u 3
We can find that in the 1st period (from a to i): max = 5, min = 1. In the 2nd period (from i to u) : max = 6, min = 0.
Using awk, I can only print the max and min of all second column, but I cannot print these values min and max after each period. That means I wish to obtain results like this :
period min max
1 1 5
2 0 6
Here is what I did :
{
nb_lignes = 21
period = 9
nb_periodes = int(nb_lignes/period)
}
{
for (j = 0; j <= nb_periodes; j++)
{ if (NR == (1 + period*j)) {{max=$2 ; min=$2}}
for (i = (period*j); i <= (period*(j+1)); i++)
{
if (NR == i)
{
if ($2 >= max) {max = $2}
if ($2 <= min) {min = $2}
{print "Min: "min,"Max: "max,"Ligne: " NR}
}
}
}
}
#END { print "Min: "min,"Max: "max }
However the result is far away from what I search for :
Min: 3 Max: 3 Ligne: 1
Min: 3 Max: 4 Ligne: 2
Min: 3 Max: 5 Ligne: 3
Min: 3 Max: 5 Ligne: 4
Min: 3 Max: 5 Ligne: 5
Min: 2 Max: 5 Ligne: 6
Min: 1 Max: 5 Ligne: 7
Min: 1 Max: 5 Ligne: 8
Min: 1 Max: 5 Ligne: 9
Min: 1 Max: 5 Ligne: 9
Min: 4 Max: 4 Ligne: 10
Min: 4 Max: 5 Ligne: 11
Min: 4 Max: 6 Ligne: 12
Min: 4 Max: 6 Ligne: 13
Min: 4 Max: 6 Ligne: 14
Min: 3 Max: 6 Ligne: 15
Min: 2 Max: 6 Ligne: 16
Min: 1 Max: 6 Ligne: 17
Min: 0 Max: 6 Ligne: 18
Min: 0 Max: 6 Ligne: 18
Min: 1 Max: 1 Ligne: 19
Min: 1 Max: 2 Ligne: 20
Min: 1 Max: 3 Ligne: 21
Thank you in advance for you help.
Upvotes: 2
Views: 181
Reputation: 74705
I've started, so I'll finish. I chose to create an array which contains the minimum and maximum for each period:
awk -v period=9 '
BEGIN { print "period", "min", "max" }
NR % period == 1 { ++i }
!min[i] || $2 < min[i] { min[i] = $2 }
$2 > max[i] { max[i] = $2 }
END { for (i in min) print i, min[i], max[i] }' input
The index i
increases every period
number of lines (in this case 9
). If no value has been set yet or a new minimum/maximum has been found, update the array.
edit: if max[i]
has not yet been set then $2 > max[i]
, so no need to check !max[i]
.
Upvotes: 1
Reputation: 67319
awk 'BEGIN{print "Period","min","max"}
NR==1||(NR%10==0){mi=ma=$2}
{$2<mi?mi=$2:0;$2>ma?ma=$2:0}
NR%9==0{print ++i,mi,ma}' your_file
Tester here
Upvotes: 0
Reputation: 77185
Try something like:
$ awk '
BEGIN{print "period", "min", "max"}
!f{min=$2; max=$2; ++f; next}
{max = ($2>max)?$2:max; min = ($2<min)?$2:min; f++}
f==9{print ++a, min, max; f=0}' file
period min max
1 1 5
2 0 6
f
is not set, you assign the second column to max and min variables and start incrementing your flag. Upvotes: 1