padding left-justified string fields

[Dave]

I've written a perl program to manipulate data formats so that I can import
data from an estimating software program to an accounting program. Works
just fine, with the following caveat: The record identifier field is
numeric in the estimating program but it can be (and is interpreted as) a
string in the accounting software. Hence, when I bring up project data in
the accounting software, my items look like so:

10
100
110
....
190
20
210
220

These fields MUST be left-justified for importation into the account s/w, so
I am using "@<<<<<<" in my format block. I'd like to be able to pad all
items to four decimal places with zeroes so that I'd end up with:

010
020
030
....
090
100
etc.

Can anyone tell me of a simple way to do this in perl? I've read and read
and read the manpages on printf() and sprintf() but can't seem to figure out
the syntax. Basically I'm printing out 19 fields, the first three are
left-justified (strings) with varying lengths and the rest for the most part
are seven-dot-three numerics. It would have been easier I'm sure to use
printf with some modifiers rather than type in all those "###'s" and
"<<<'s". Can anyone point me to an online resource to figure out printf
with some real world examples?

Thanks

Dave

 

[Joe Smith]

I'd like to be able to pad all items to 3 decimal places with zeroes
Can anyone tell me of a simple way to do this in perl?

It's simple.

printf "%03d %4d %s\n", $number1, $number2, $string;

That will make $number1 be padded to three places with zeros
and $number2 padded to four places with spaces, followed
by a string and ending with a newline.
-Joe

 

[Dave]

It's simple.

printf "%03d %4d %s\n", $number1, $number2, $string;

Thanks Joe. Can you tell me how to specify left vs. right-justified with
printf? Also, if I have a 7-dot-3 decimal format, is it possible to specify
the location of the decimal point?

thx

Dave

 

[Jürgen Exner]

[...] Can you tell me how to specify left vs. right-justified
with printf? Also, if I have a 7-dot-3 decimal format, is it
possible to specify the location of the decimal point?

Did you check "perldoc -f sprintf" as suggested in "perldoc -f printf"?

jue

 

[Dave]

It's simple.

printf "%03d %4d %s\n", $number1, $number2, $string;

That will make $number1 be padded to three places with zeros
and $number2 padded to four places with spaces, followed
by a string and ending with a newline.

Okay, that's all good. But my predicament is that I want something like
"10" padded to "010" AND I want it left-justified... the manpage for printf
states "If the 0 and - flags both appear, the 0 flag is ignored." Also, my
input format requires fixed-width fields; hence if I've got "10" and I
choose pad (i.e. printf "%010d") I end up with 0000000010 which I definitely
don't want imported as my string.

I guess maybe I could use printf to pad my values, then format to output
properly re: left-justification, etc.

 

[Dave]

[...] Can you tell me how to specify left vs. right-justified
with printf? Also, if I have a 7-dot-3 decimal format, is it
possible to specify the location of the decimal point?

Did you check "perldoc -f sprintf" as suggested in "perldoc -f printf"?

jue

I did. I swear it. I tried many combinations and permutations. I ended up
using a two-step approach: I used printf to pad my values as part of my
array assignment loop, then format/write for justification and field
placement. I could use printf twice, but already had the output format all
set up for write. This approach ended up being the simplest for me, not
being skilled in the ways of printf.

I can see that in the big picture, printf is much more economical (saves
many many keystrokes) and I will probably put some time into broadening my
understanding of it.

 

[Joe Smith]

[...] Can you tell me how to specify left vs. right-justified
with printf? Also, if I have a 7-dot-3 decimal format, is it
possible to specify the location of the decimal point?

Did you check "perldoc -f sprintf" as suggested in "perldoc -f printf"?

jue

I did. I swear it.

You didn't read all of it.

You've missed the line with "left-justify within the field".
Go back and read it again.
-Joe

 

[Joe Smith]

Okay, that's all good. But my predicament is that I want something like
"10" padded to "010" AND I want it left-justified... the manpage for printf
states "If the 0 and - flags both appear, the 0 flag is ignored."

It appears you did not recognize the significance of this line:

.number "precision": digits after decimal point for
floating-point, max length for string, minimum length
for integer

That line explains what you should expect from
printf "%10.3\n",99;

-Joe