Why does cqlsh right-align strings?

问题

I find that string-values displayed using cqlsh are right-aligned. Is there a reason for this? And is there a way to left-align strings?

cqlsh:test> create table test (id int, a ascii, t text, primary key(id));
cqlsh:test> insert into test (id, a, t) values (1, 'ascii', 'text');
cqlsh:test> insert into test (id, a, t) values (2, 'a', 't');       
cqlsh:test> select * from test;                              

 id | a     | t
----+-------+------
  1 | ascii | text
  2 |     a |    t

(2 rows)

回答1:

I think this is mostly done for aesthetic reasons, however you can change it!

cqlsh is simply a python file that uses the python-driver. You can simply change the following code in the print_formatted_result method of cqlsh:

    for row in formatted_values:                                                
        line = ' | '.join(col.rjust(w, color=self.color) for (col, w) in zip(row, widths))
        self.writeresult(' ' + line)

You can change col.rjust to ljust, center, etc. or you can simply change it to 'col' to print the data as is.

Example using ljust:

cqlsh:friends> select * from group_friends;

 groupid                              | friendid | time
--------------------------------------+----------+--------
 13814000-1dd2-11b2-8080-808080808080 | 1        | 123456
 13814000-1dd2-11b2-8080-808080808080 | 2        | 123456
 13814000-1dd2-11b2-8080-808080808080 | 4        | 123456
 13814000-1dd2-11b2-8080-808080808080 | 8        | 123456
 13814000-1dd2-11b2-8080-808080808080 | 22       | 123456
 13814000-1dd2-11b2-8080-808080808080 | 1002     | 123456

回答2:

Try using the shell's column program to align columns:

$CASSANDRA_HOME/bin/cqlsh <<EOF | grep -v '+--'  | perl -pe 's{[ ]{4,}}{|}g' | column -t -s '|' | tee out.txt
    select mycol1,mycol2 from mykeyspace.mytable;
EOF

Use a here document to send input to cqlsh
Removing excess spaces with your favorite regex tool (but be careful not to remove them in your data)
Align fields based on | as the separator / delimiter using the column program
(Optional) Copy the output to a txt file using tee

来源：https://stackoverflow.com/questions/28848315/why-does-cqlsh-right-align-strings

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