How to Print "Pretty" String Output in Python

Question

I have a list of dicts with the fields classid, dept, coursenum, area, and title from a sql query. I would like to output the values in a human readable format. I was thinking a Column header at the top of each and then in each column the approrpiate output ie:

CLASSID     DEPT     COURSE NUMBER        AREA     TITLE foo         bar      foo                  bar      foo yoo         hat      yoo                  bar      hat 

(obviously with standard alignment/spacing)

How would I accomplish this in python?

Answer 1

Standard Python string formatting may suffice.

# assume that your data rows are tuples template = "{0:8}|{1:10}|{2:15}|{3:7}|{4:10}" # column widths: 8, 10, 15, 7, 10 print template.format("CLASSID", "DEPT", "COURSE NUMBER", "AREA", "TITLE") # header for rec in your_data_source:    print template.format(*rec) 

Or

# assume that your data rows are dicts template = "{CLASSID:8}|{DEPT:10}|{C_NUM:15}|{AREA:7}|{TITLE:10}" # same, but named print template.format( # header   CLASSID="CLASSID", DEPT="DEPT", C_NUM="COURSE NUMBER",    AREA="AREA", TITLE="TITLE" )  for rec in your_data_source:    print template.format(**rec) 

Play with alignment, padding, and exact format specifiers to get best results.

Answer 2

class TablePrinter(object):     "Print a list of dicts as a table"     def __init__(self, fmt, sep=' ', ul=None):         """                 @param fmt: list of tuple(heading, key, width)                         heading: str, column label                         key: dictionary key to value to print                         width: int, column width in chars         @param sep: string, separation between columns         @param ul: string, character to underline column label, or None for no underlining         """         super(TablePrinter,self).__init__()         self.fmt   = str(sep).join('{lb}{0}:{1}{rb}'.format(key, width, lb='{', rb='}') for heading,key,width in fmt)         self.head  = {key:heading for heading,key,width in fmt}         self.ul    = {key:str(ul)*width for heading,key,width in fmt} if ul else None         self.width = {key:width for heading,key,width in fmt}      def row(self, data):         return self.fmt.format(**{ k:str(data.get(k,''))[:w] for k,w in self.width.iteritems() })      def __call__(self, dataList):         _r = self.row         res = [_r(data) for data in dataList]         res.insert(0, _r(self.head))         if self.ul:             res.insert(1, _r(self.ul))         return '\n'.join(res) 

and in use:

data = [     {'classid':'foo', 'dept':'bar', 'coursenum':'foo', 'area':'bar', 'title':'foo'},     {'classid':'yoo', 'dept':'hat', 'coursenum':'yoo', 'area':'bar', 'title':'hat'},     {'classid':'yoo'*9, 'dept':'hat'*9, 'coursenum':'yoo'*9, 'area':'bar'*9, 'title':'hathat'*9} ]  fmt = [     ('ClassID',       'classid',   11),     ('Dept',          'dept',       8),     ('Course Number', 'coursenum', 20),     ('Area',          'area',       8),     ('Title',         'title',     30) ]  print( TablePrinter(fmt, ul='=')(data) ) 

produces

ClassID     Dept     Course Number        Area     Title                          =========== ======== ==================== ======== ============================== foo         bar      foo                  bar      foo                            yoo         hat      yoo                  bar      hat                            yooyooyooyo hathatha yooyooyooyooyooyooyo barbarba hathathathathathathathathathat