Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>After staring at this for over an hour, comparing two nearly identical versions, one that worked, one that didn't, I am able to make it fail or succeed by commenting out a single line. here is the exact code I am running: [Edit note, altered the code to prevent vertical scroll bar in code sample]</p> <pre><code>#!/usr/local/bin/ruby my_input ="ATT Wireless Bill\n\nMobile Number:,770-555-1212\n\nitem,date,time,number called,rate period,plan type,minutes,airtime charge,ld charge,total charge\n\n1,2011-01-02,6:56AM,404-555-1212,NW,UNW,4,0.00,0.00,0.00\n\n" my_input &lt;&lt; "2,2011-01-03,6:56AM,404-555-1212,NW,UNW,4,0.00,0.00,0.00\n\n1,2011-01-03,7:56AM,404-555-1213,DT,UM2M,5,0.00,0.00,0.00\n\nMobile Number:,770-555-1213\n\nitem,date,time,number called,rate period,plan type,minutes,airtime charge,ld charge,total charge\n\n" my_input &lt;&lt; "1,2011-01-02,6:56AM,404-555-1212,NW,UNW,4,0.00,0.00,0.00\n\n2,2011-01-03,6:56AM,404-555-1212,NW,UNW,4,0.00,0.00,0.00\n\n1,2011-01-03,7:56AM,404-555-1213,DT,UM2M,5,0.00,0.00,0.00\n\n" lines = my_input.split("\n") count = 0 cur_num = "" # Line 7 - Comment out this line to see failure lines.each do |line| unless (line.strip.eql?("")) if (line.slice(0,15) == "Mobile Number:,") cur_num = line.slice(15,12) count = 1 puts "Current Number: #{cur_num}" #puts "Object Type: #{cur_num.class}" else data = line.strip.split(',') if (data.length &gt; 8) data.unshift(cur_num) #if (count.modulo(10) == 0 || count == 1) puts "[#{cur_num}] #{data.inspect}" #pp data #end count += 1 end end end end </code></pre> <p>If I comment out line 7, then cur_val is nil on lines 18 and 20.</p> <p>Can someone please explain why?</p>
    singulars
    1. This table or related slice is empty.
    1. POWhy / How is my variable getting set to nil
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USScott
    1. USScott
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. COWithout `cur_num = "" ` you don't initialize cur_num (it is nil). Your loop start without `Current Number:`, so you go to the else-branch (with cur_num = nil).
      singulars
      1. PO
      1. USknut
    2. CO-----sorry , wrong posting ---
      singulars
      1. PO
      1. USknut
    3. COI do not understad. cur_num gets initiated before the unshift statement of line 18 - it should not be nil at that point. And why, if I set to an empty string before the each iteration, is it not then an empty string at line 18. This appears inconsistent to me, and I suspect that this an important concept necessary to understanding Ruby.
      singulars
      1. PO
      1. USScott
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload