How to move decimal point in bash

up vote
3
down vote

favorite

I have a variable that is stored as "1.20E20". I would like for it to be changed to "0.0120E22". Is there a simple command to change this value? I tried

let nh=$nh/100

But that did not work; I assume it is because of the character value in the variable. I know there are various solutions; what is the best way to solve this?

edited Jun 6 at 18:16

asked Jun 6 at 18:04

J. Doe

937

1

do you need to change it to 0.120E21? Do you want to divide it by ten, or just express the same value with a different form?
â€“Â glenn jackman
Jun 6 at 18:11

@glennjackman Yes, I need it to change to 0.012E22 (I messed up slightly in the original question, but you were right in assuming).
â€“Â J. Doe
Jun 6 at 18:20

Technically, a number in scientific notation is supposed to be xEy or x Ã¢Â€Â¢ 10^y, where 1 < x < 10 and y is the power of ten.
â€“Â juniorRubyist
Jun 7 at 4:19

add a commentÂ |Â

up vote
3
down vote

favorite

I have a variable that is stored as "1.20E20". I would like for it to be changed to "0.0120E22". Is there a simple command to change this value? I tried

let nh=$nh/100

But that did not work; I assume it is because of the character value in the variable. I know there are various solutions; what is the best way to solve this?

edited Jun 6 at 18:16

asked Jun 6 at 18:04

J. Doe

937

1

do you need to change it to 0.120E21? Do you want to divide it by ten, or just express the same value with a different form?
â€“Â glenn jackman
Jun 6 at 18:11

@glennjackman Yes, I need it to change to 0.012E22 (I messed up slightly in the original question, but you were right in assuming).
â€“Â J. Doe
Jun 6 at 18:20

Technically, a number in scientific notation is supposed to be xEy or x Ã¢Â€Â¢ 10^y, where 1 < x < 10 and y is the power of ten.
â€“Â juniorRubyist
Jun 7 at 4:19

add a commentÂ |Â

up vote
3
down vote

favorite

I have a variable that is stored as "1.20E20". I would like for it to be changed to "0.0120E22". Is there a simple command to change this value? I tried

let nh=$nh/100

But that did not work; I assume it is because of the character value in the variable. I know there are various solutions; what is the best way to solve this?

edited Jun 6 at 18:16

asked Jun 6 at 18:04

J. Doe

937

I have a variable that is stored as "1.20E20". I would like for it to be changed to "0.0120E22". Is there a simple command to change this value? I tried

let nh=$nh/100

But that did not work; I assume it is because of the character value in the variable. I know there are various solutions; what is the best way to solve this?

edited Jun 6 at 18:16

asked Jun 6 at 18:04

J. Doe

937

edited Jun 6 at 18:16

asked Jun 6 at 18:04

J. Doe

937

asked Jun 6 at 18:04

J. Doe

937

asked Jun 6 at 18:04

J. Doe

937

1

do you need to change it to 0.120E21? Do you want to divide it by ten, or just express the same value with a different form?
â€“Â glenn jackman
Jun 6 at 18:11

@glennjackman Yes, I need it to change to 0.012E22 (I messed up slightly in the original question, but you were right in assuming).
â€“Â J. Doe
Jun 6 at 18:20

Technically, a number in scientific notation is supposed to be xEy or x Ã¢Â€Â¢ 10^y, where 1 < x < 10 and y is the power of ten.
â€“Â juniorRubyist
Jun 7 at 4:19

add a commentÂ |Â

1

do you need to change it to 0.120E21? Do you want to divide it by ten, or just express the same value with a different form?
â€“Â glenn jackman
Jun 6 at 18:11

@glennjackman Yes, I need it to change to 0.012E22 (I messed up slightly in the original question, but you were right in assuming).
â€“Â J. Doe
Jun 6 at 18:20

Technically, a number in scientific notation is supposed to be xEy or x Ã¢Â€Â¢ 10^y, where 1 < x < 10 and y is the power of ten.
â€“Â juniorRubyist
Jun 7 at 4:19

do you need to change it to 0.120E21? Do you want to divide it by ten, or just express the same value with a different form?
â€“Â glenn jackman
Jun 6 at 18:11

@glennjackman Yes, I need it to change to 0.012E22 (I messed up slightly in the original question, but you were right in assuming).
â€“Â J. Doe
Jun 6 at 18:20

Technically, a number in scientific notation is supposed to be xEy or x Ã¢Â€Â¢ 10^y, where 1 < x < 10 and y is the power of ten.
â€“Â juniorRubyist
Jun 7 at 4:19

add a commentÂ |Â

2 Answers
2

active

oldest

votes

up vote
6
down vote

accepted

I don't know of a way to force printf to shift the exponent. Let's do it manually: multiply the coefficient by 10^-2, and add 2 to the exponent.

n=1.20E20
m=2
IFS="E" read coeff exp <<<"$n"
new=$(printf "%.4fE%dn" "$(echo "$coeff * 10^-($m)" | bc -l)" "$((exp+m))")
# => 0.0120E22

We can validate with:

$ printf "%en" "$new"
1.200000e+20

edited Jun 6 at 22:34

dessert

19.4k55494

answered Jun 6 at 18:29

glenn jackman

11.7k2241

add a commentÂ |Â

up vote
2
down vote

IÃ¢Â€Â™d write a simple bash script like this:

#!/bin/bash
a=$1%E*
b=$1#*E
echo 0$(<<<"scale=4;$a/10^$2" bc)E$((b+$2))

You just need to give it the values as arguments, first the number and then the shift:

$ bash /path/to/script 1.20E20 2
0.0120E22
 # or, as a oneliner:
$ bash -c 'echo 0$(<<<"scale=4;$1%E*/10^$2" bc)E$(($1#*E+$2))' _ 1.20E20 2
0.0120E22

edited Jun 6 at 18:50

answered Jun 6 at 18:16

dessert

19.4k55494

add a commentÂ |Â

Your Answer

StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "89"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);

else
createEditor();

);

function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
convertImagesToLinks: true,
noModals: false,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);

);

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');

var $window = $(window),
onScroll = function(e)
var $elem = $('.new-login-left'),
docViewTop = $window.scrollTop(),
docViewBottom = docViewTop + $window.height(),
elemTop = $elem.offset().top,
elemBottom = elemTop + $elem.height();
if ((docViewTop elemBottom))
StackExchange.using('gps', function() StackExchange.gps.track('embedded_signup_form.view', location: 'question_page' ); );
$window.unbind('scroll', onScroll);

;
$window.on('scroll', onScroll);

);

StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2faskubuntu.com%2fquestions%2f1044251%2fhow-to-move-decimal-point-in-bash%23new-answer', 'question_page');

);

Post as a guest

Name

2 Answers
2

active

oldest

votes

2 Answers
2

active

oldest

votes

up vote
6
down vote

accepted

I don't know of a way to force printf to shift the exponent. Let's do it manually: multiply the coefficient by 10^-2, and add 2 to the exponent.

n=1.20E20
m=2
IFS="E" read coeff exp <<<"$n"
new=$(printf "%.4fE%dn" "$(echo "$coeff * 10^-($m)" | bc -l)" "$((exp+m))")
# => 0.0120E22

We can validate with:

$ printf "%en" "$new"
1.200000e+20

edited Jun 6 at 22:34

dessert

19.4k55494

answered Jun 6 at 18:29

glenn jackman

11.7k2241

add a commentÂ |Â

up vote
6
down vote

accepted

I don't know of a way to force printf to shift the exponent. Let's do it manually: multiply the coefficient by 10^-2, and add 2 to the exponent.

n=1.20E20
m=2
IFS="E" read coeff exp <<<"$n"
new=$(printf "%.4fE%dn" "$(echo "$coeff * 10^-($m)" | bc -l)" "$((exp+m))")
# => 0.0120E22

We can validate with:

$ printf "%en" "$new"
1.200000e+20

edited Jun 6 at 22:34

dessert

19.4k55494

answered Jun 6 at 18:29

glenn jackman

11.7k2241

add a commentÂ |Â

up vote
6
down vote

accepted

I don't know of a way to force printf to shift the exponent. Let's do it manually: multiply the coefficient by 10^-2, and add 2 to the exponent.

n=1.20E20
m=2
IFS="E" read coeff exp <<<"$n"
new=$(printf "%.4fE%dn" "$(echo "$coeff * 10^-($m)" | bc -l)" "$((exp+m))")
# => 0.0120E22

We can validate with:

$ printf "%en" "$new"
1.200000e+20

edited Jun 6 at 22:34

dessert

19.4k55494

answered Jun 6 at 18:29

glenn jackman

11.7k2241

I don't know of a way to force printf to shift the exponent. Let's do it manually: multiply the coefficient by 10^-2, and add 2 to the exponent.

n=1.20E20
m=2
IFS="E" read coeff exp <<<"$n"
new=$(printf "%.4fE%dn" "$(echo "$coeff * 10^-($m)" | bc -l)" "$((exp+m))")
# => 0.0120E22

We can validate with:

$ printf "%en" "$new"
1.200000e+20

edited Jun 6 at 22:34

dessert

19.4k55494

answered Jun 6 at 18:29

glenn jackman

11.7k2241

edited Jun 6 at 22:34

dessert

19.4k55494

edited Jun 6 at 22:34

dessert

19.4k55494

edited Jun 6 at 22:34

dessert

19.4k55494

answered Jun 6 at 18:29

glenn jackman

11.7k2241

answered Jun 6 at 18:29

glenn jackman

11.7k2241

answered Jun 6 at 18:29

glenn jackman

11.7k2241

add a commentÂ |Â

up vote
2
down vote

IÃ¢Â€Â™d write a simple bash script like this:

#!/bin/bash
a=$1%E*
b=$1#*E
echo 0$(<<<"scale=4;$a/10^$2" bc)E$((b+$2))

You just need to give it the values as arguments, first the number and then the shift:

$ bash /path/to/script 1.20E20 2
0.0120E22
 # or, as a oneliner:
$ bash -c 'echo 0$(<<<"scale=4;$1%E*/10^$2" bc)E$(($1#*E+$2))' _ 1.20E20 2
0.0120E22

edited Jun 6 at 18:50

answered Jun 6 at 18:16

dessert

19.4k55494

add a commentÂ |Â

up vote
2
down vote

IÃ¢Â€Â™d write a simple bash script like this:

#!/bin/bash
a=$1%E*
b=$1#*E
echo 0$(<<<"scale=4;$a/10^$2" bc)E$((b+$2))

You just need to give it the values as arguments, first the number and then the shift:

$ bash /path/to/script 1.20E20 2
0.0120E22
 # or, as a oneliner:
$ bash -c 'echo 0$(<<<"scale=4;$1%E*/10^$2" bc)E$(($1#*E+$2))' _ 1.20E20 2
0.0120E22

edited Jun 6 at 18:50

answered Jun 6 at 18:16

dessert

19.4k55494

add a commentÂ |Â

up vote
2
down vote

IÃ¢Â€Â™d write a simple bash script like this:

#!/bin/bash
a=$1%E*
b=$1#*E
echo 0$(<<<"scale=4;$a/10^$2" bc)E$((b+$2))

You just need to give it the values as arguments, first the number and then the shift:

$ bash /path/to/script 1.20E20 2
0.0120E22
 # or, as a oneliner:
$ bash -c 'echo 0$(<<<"scale=4;$1%E*/10^$2" bc)E$(($1#*E+$2))' _ 1.20E20 2
0.0120E22

edited Jun 6 at 18:50

answered Jun 6 at 18:16

dessert

19.4k55494

IÃ¢Â€Â™d write a simple bash script like this:

#!/bin/bash
a=$1%E*
b=$1#*E
echo 0$(<<<"scale=4;$a/10^$2" bc)E$((b+$2))

You just need to give it the values as arguments, first the number and then the shift:

$ bash /path/to/script 1.20E20 2
0.0120E22
 # or, as a oneliner:
$ bash -c 'echo 0$(<<<"scale=4;$1%E*/10^$2" bc)E$(($1#*E+$2))' _ 1.20E20 2
0.0120E22

edited Jun 6 at 18:50

answered Jun 6 at 18:16

dessert

19.4k55494

edited Jun 6 at 18:50

answered Jun 6 at 18:16

dessert

19.4k55494

answered Jun 6 at 18:16

dessert

19.4k55494

answered Jun 6 at 18:16

dessert

19.4k55494

add a commentÂ |Â

draft saved

draft discarded

draft saved

draft discarded

Sign up or log in

Post as a guest

Name

Sign up or log in

Name

搜尋此網誌

Gfilui