# Format problem

**URL:** <https://www.ruby-forum.com/t/format-problem/176284>\
**Category:** Ruby\
**Created:** [September 28, 2009, 3:38pm UTC](https://www.ruby-forum.com/t/format-problem/176284 "2009-09-28T15:38:47Z")\
**Posts on this page:** 8\
**Page:** 1

<div class="post-metadata">

**Author:** ![alex-osu3](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/13edae/32.png) [@alex-osu3](https://www.ruby-forum.com/u/alex-osu3)\
**Post date:** [September 28, 2009, 3:38pm UTC](https://www.ruby-forum.com/t/format-problem/176284/1 "2009-09-28T15:38:47Z")

</div>

Hi all,

I have an 2D array and I write it a file using the following script. But  
when I open the written file I find the format is not what I want: the  
second and third row are not justified as the first row. I wonder how to  
correct it.

Thanks,

Li

############  
c=[[‘a’,‘b’,‘c’],[‘c1’,2,1],[‘d1’,3,4] ]  
c.collect!{|row| row\<\<"\n"}

File.open(‘test.txt’,‘w’) do |a\_file|  
c.each do |row|  
row.each {|e| ("#{e}"=~/[a-zA-Z]|\n/) ?  
(a\_file.printf("%s\t",e)) : ( a\_file.printf("%.2f\t",e)) }  
end  
end

########output#############

a b c  
c1 2.00 1.00  
d1 3.00 4.00

####expected as follow########  
a b c  
c1 2.00 1.00  
d1 3.00 4.00

---

<div class="post-metadata">

**Author:** ![alex-osu3](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/13edae/32.png) [@alex-osu3](https://www.ruby-forum.com/u/alex-osu3)\
**Post date:** [September 28, 2009, 5:33pm UTC](https://www.ruby-forum.com/t/format-problem/176284/2 "2009-09-28T17:33:40Z")

</div>

Think about what’s happening when you add a newline to that row. How  
will that  
newline be printed? Specifically, which printf statement are you using?

---

<div class="post-metadata">

**Author:** ![alex-osu3](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/13edae/32.png) [@alex-osu3](https://www.ruby-forum.com/u/alex-osu3)\
**Post date:** [September 28, 2009, 5:34pm UTC](https://www.ruby-forum.com/t/format-problem/176284/3 "2009-09-28T17:34:16Z")

</div>

At 2009-09-28 09:38AM, “Li Chen” wrote:

> c=[[‘a’,‘b’,‘c’],[‘c1’,2,1],[‘d1’,3,4] ]  
> c.collect!{|row| row\<\<"\n"}
> 
> File.open(‘test.txt’,‘w’) do |a\_file|  
> c.each do |row|  
> row.each {|e| ("#{e}"=~/[a-zA-Z]|\n/) ?  
> (a\_file.printf("%s\t",e)) : ( a\_file.printf("%.2f\t",e)) }  
> end  
> end

You might try checking if the element is a number, otherwise treat it as  
a string:

```
c.each do |row|
  row.each do |elem|
    fmt = Numeric === elem ? "%.2f\t" : "%s\t"
    a_file.printf(fmt, elem)
  end
  a_file.puts
end
```

---

<div class="post-metadata">

**Author:** ![alex-osu3](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/13edae/32.png) [@alex-osu3](https://www.ruby-forum.com/u/alex-osu3)\
**Post date:** [September 28, 2009, 8:15pm UTC](https://www.ruby-forum.com/t/format-problem/176284/4 "2009-09-28T20:15:16Z")

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Glenn J. wrote:

> At 2009-09-28 09:38AM, “Li Chen” wrote:
> 
> > c=[[‘a’,‘b’,‘c’],[‘c1’,2,1],[‘d1’,3,4] ]  
> > c.collect!{|row| row\<\<"\n"}
> > 
> > File.open(‘test.txt’,‘w’) do |a\_file|  
> > c.each do |row|  
> > row.each {|e| ("#{e}"=~/[a-zA-Z]|\n/) ?  
> > (a\_file.printf("%s\t",e)) : ( a\_file.printf("%.2f\t",e)) }  
> > end  
> > end
> 
> You might try checking if the element is a number, otherwise treat it as  
> a string:
> 
> ```
> c.each do |row|
> row.each do |elem|
> fmt = Numeric === elem ? "%.2f\t" : "%s\t"
> a_file.printf(fmt, elem)
> end
> a_file.puts
> end
> 
> ```

Hi Glen,

I think I do try to check if the element is a number by this code:  
("#{e}"=~/[a-zA-Z]|\n/) ?  
(a\_file.printf("%s\t",e)) : ( a\_file.printf("%.2f\t",e))

It looks different from yours:  
fmt = Numeric === elem ? “%.2f\t” : “%s\t”

So what is the real different here? Why do you use a code line  
Numeric===elem ?

Thanks,

Li

---

<div class="post-metadata">

**Author:** ![alex-osu3](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/13edae/32.png) [@alex-osu3](https://www.ruby-forum.com/u/alex-osu3)\
**Post date:** [September 28, 2009, 11:59pm UTC](https://www.ruby-forum.com/t/format-problem/176284/5 "2009-09-28T23:59:30Z")

</div>

David M. wrote:

> Does that make sense?

Hi David,

Thank you very much and now I get it.

Li

---

<div class="post-metadata">

**Author:** ![alex-osu3](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/13edae/32.png) [@alex-osu3](https://www.ruby-forum.com/u/alex-osu3)\
**Post date:** [September 28, 2009, 11:40pm UTC](https://www.ruby-forum.com/t/format-problem/176284/6 "2009-09-28T23:40:08Z")

</div>

On Monday 28 September 2009 01:15:18 pm Li Chen wrote:

> I think I do try to check if the element is a number by this code:  
> ("#{e}"=~/[a-zA-Z]|\n/) ?  
> (a\_file.printf("%s\t",e)) : ( a\_file.printf("%.2f\t",e))

That’s not your issue.

I did give you a hint: It’s about the newlines. Now I should ask: Are  
you a  
newbie? If so, there may be some value in giving you a “hint” rather  
than just  
telling you what’s wrong.

Anyway, here’s a hint: This line here:

c.collect!{|row| row\<\<"\n"}

What does c look like after that? Each row has a \n on it, right?

If it helps, add this line immediately after that collect:

p c

Now, when you run that loop, each element that includes a letter (or \n)  
will  
run through this:

a\_file.printf("%s\t", e)

What will that produce? For example,if you run ‘a’ through that, you’ll  
get  
“a\t”, right?

So if you run “\n” through that, what do you get?

Now, if you just want an answer, here’s how I’d do it:

c=[[‘a’,‘b’,‘c’],[‘c1’,2,1],[‘d1’,3,4] ]

File.open(‘test.txt’, ‘w’) do |a\_file|  
c.each do |row|  
puts row.map{|e| e.kind\_of?(Numeric) ? sprintf("%.2f", e) :  
e}.join("\t")  
end  
end

Does that make sense?

---

<div class="post-metadata">

**Author:** ![alex-osu3](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/13edae/32.png) [@alex-osu3](https://www.ruby-forum.com/u/alex-osu3)\
**Post date:** [September 29, 2009, 12:10am UTC](https://www.ruby-forum.com/t/format-problem/176284/7 "2009-09-29T00:10:14Z")

</div>

David M. wrote:

> Does that make sense?

Hi David,

Thank you for the detailed explanation and I get it. But I have another  
question:

When I open the written file I get my expected format correctly. But it  
is odd that after I open it with Excel or import it into Excel the data  
in one column are not formatted. Is it caused by Excel?

Thanks,

Li

## written file is open with notepad

a b c

c1 2.00 1.00

d1 3.00 4.00

# file is open with Excel

a b c

c1 2 1

d1 3 4

---

<div class="post-metadata">

**Author:** ![alex-osu3](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/13edae/32.png) [@alex-osu3](https://www.ruby-forum.com/u/alex-osu3)\
**Post date:** [September 29, 2009, 2:59am UTC](https://www.ruby-forum.com/t/format-problem/176284/8 "2009-09-29T02:59:12Z")

</div>

First, I should apologize for anyone following along – that should be  
a\_file.puts, not just puts.

On Monday 28 September 2009 05:10:16 pm Li Chen wrote:

> When I open the written file I get my expected format correctly. But it  
> is odd that after I open it with Excel or import it into Excel the data  
> in one column are not formatted. Is it caused by Excel?

Let’s see…

> # file is open with Excel
> 
> a b c
> 
> c1 2 1
> 
> d1 3 4

Most likely. My understanding is that Excel doesn’t make a distinction  
between  
integers and floats. For example, try creating this table:

1  
=A1/2

That second shell should be 0.5, right?

A quick experiment with OpenOffice shows the exact same behavior. I  
don’t really  
know of a good way around it. However, a few things to consider:

First, does it matter? It’s very quick to format a range of cells in  
Excel.

Second, do you really want to be doing this by hand? There’s a CSV  
generator  
in the Ruby standard library that’s at least as easy to use as what you  
came  
up with, probably easier. Watch this:

c=[[‘a’,‘b’,‘c’],[‘c1’,2,1],[‘d1’,3,4] ]

require ‘csv’  
CSV.open ‘test.txt’, ‘w’ do |a\_csv|  
c.each do |row|  
a\_csv \<\< row  
end  
end

This doesn’t fix the problem, but it avoids potential future problems –  
for  
example, if any of your strings had tabs, quotes, commas, etc, that  
library  
will take care of it.

But the fact that you’re using exactly two decimal places for  
everything, and  
you’re in Excel, tells me this is probably currency of some kind, right?  
One  
possible workaround I noticed is this:

c=[[‘a’,‘b’,‘c’],[‘c1’,2,1],[‘d1’,3,4] ]

require ‘csv’  
CSV.open ‘test.txt’, ‘w’ do |csv|  
c.each do |row|  
csv \<\< row.map{|x| x.kind\_of?(Numeric) ? “$#{x}” : x}  
end  
end

That adds a dollarsign to all the numbers. Without even adding decimal  
places,  
OpenOffice suddenly sees them as $1.00, $2.00, etc.

Hope that helps.

If Excel behaves differently, I’m not really sure what to tell you…