Formatting a list of text into columns

Question

I'm trying to output a list of string values into a 2 column format. The standard way of making a list of strings into "normal text" is by using the string.join method. However, it only takes 2 arguments so I can only make a single column using "\n". I thought trying to make a loop that would simply add a tab between columns would do it but the logic didn't work correctly.

I found an ActiveState page that has a fairly complicated way of doing it but it's from 4 years ago. Is there an easy way to do it nowadays?

Edit Here is the list that I want to use.

skills_defs = ["ACM:Aircraft Mechanic", "BC:Body Combat", "BIO:Biology",
    "CBE:Combat Engineer", "CHM:Chemistry", "CMP:Computers", 
    "CRM:Combat Rifeman", "CVE:Civil Engineer", "DIS:Disguise",
    "ELC:Electronics","EQ:Equestrian", "FO:Forward Observer",
    "FOR:Forage", "FRG:Forgery", "FRM:Farming", "FSH:Fishing",
    "GEO:Geology", "GS:Gunsmith", "HW:Heavy Weapons", "IF:Indirect Fire",
    "INS:Instruction", "INT:Interrogation", "JP:Jet Pilot", "LB:Longbow",
    "LAP:Light Aircraft Pilot", "LCG:Large Caliber Gun", "LNG:Language",
    "LP:Lockpick", "MC:Melee Combat", "MCY:Motorcycle", "MEC:Mechanic",
    "MED:Medical", "MET:Meterology", "MNE:Mining Engineer",
    "MTL:Metallurgy", "MTN:Mountaineering", "NWH:Nuclear Warhead",
    "PAR:Parachute", "PST:Pistol", "RCN:Recon", "RWP:Rotary Wing Pilot",
    "SBH:Small Boat Handling","SCD:Scuba Diving", "SCR:Scrounging",
    "SWM:Swimming", "TW:Thrown Weapon", "TVD:Tracked Vehicle Driver",
    "WVD:Wheeled Vehicle Driver"]

I just want to output this list into a simple, 2 column format to reduce space. Ideally there should be a standard amount of space between the columns but I can work with it.

ACM:Aircraft Mechanic        BC:Body Combat 
BIO:Biology         CBE:Combat Engineer 
CHM:Chemistry       CMP:Computers
CRM:Combat Rifeman      CVE:Civil Engineer 
DIS:Disguise            ELC:Electronics 
EQ:Equestrian           FO:Forward Observer
FOR:Forage          FRG:Forgery 
FRM:Farming             FSH:Fishing
GEO:Geology             GS:Gunsmith 
HW:Heavy Weapons        IF:Indirect Fire
INS:Instruction             INT:Interrogation 
JP:Jet Pilot            LB:Longbow
 LAP:Light Aircraft Pilot       LCG:Large Caliber Gun 
LNG:Language            LP:Lockpick 
MC:Melee Combat         MCY:Motorcycle 
MEC:Mechanic            MED:Medical 
MET:Meterology      MNE:Mining Engineer
MTL:Metallurgy      MTN:Mountaineering 
NWH:Nuclear Warhead     PAR:Parachute 
PST:Pistol          RCN:Recon 
RWP:Rotary Wing Pilot       SBH:Small Boat Handling 
SCD:Scuba Diving        SCR:Scrounging
SWM:Swimming        TW:Thrown Weapon 
TVD:Tracked Vehicle Driver  WVD:Wheeled Vehicle Driver

Could you provide the actual input value and the expected output format? It's not very clear what your input list looks like. — S.Lott, Oct 06 '08 at 00:59

score 11 · Answer 1 · edited May 23 '17 at 12:10

Two columns, separated by tabs, joined into lines. Look in itertools for iterator equivalents, to achieve a space-efficient solution.

import string
def fmtpairs(mylist):
    pairs = zip(mylist[::2],mylist[1::2])
    return '\n'.join('\t'.join(i) for i in pairs)

print fmtpairs(list(string.ascii_uppercase))

A   B
C   D
E   F
G   H
I   J
...

Oops... got caught by S.Lott (thank you).

A more general solution, handles any number of columns and odd lists. Slightly modified from S.lott, using generators to save space.

def fmtcols(mylist, cols):
    lines = ("\t".join(mylist[i:i+cols]) for i in xrange(0,len(mylist),cols))
    return '\n'.join(lines)

The second part of this is great! – Richard Oct 07 '12 at 12:25 — Richard, Oct 07 '12 at 12:25

ruwan800 · Answer 2 · 2018-02-23T06:08:09.130

4

This works

it = iter(skills_defs)
for i in it:
    print('{:<60}{}'.format(i, next(it, "")))

See: String format examples

edited Feb 23 '18 at 06:08

answered Oct 04 '12 at 06:34

ruwan800

901
13
18

score 3 · Answer 3 · answered Oct 06 '08 at 10:33

It's long-winded, so I'll break it into two parts.

def columns( skills_defs, cols=2 ):
    pairs = [ "\t".join(skills_defs[i:i+cols]) for i in range(0,len(skills_defs),cols) ]
    return "\n".join( pairs )

It can, obviously, be done as a single loooong statement.

This works for an odd number of skills, also.

masat · Answer 4 · 2014-07-22T00:27:48.453

3

Here is an extension of the solution provided by gimel, which allows to print equally spaced columns.

def fmtcols(mylist, cols):
    maxwidth = max(map(lambda x: len(x), mylist))
    justifyList = map(lambda x: x.ljust(maxwidth), mylist)
    lines = (' '.join(justifyList[i:i+cols]) 
             for i in xrange(0,len(justifyList),cols))
    print "\n".join(lines)

which returns something like this

ACM:Aircraft Mechanic BC:Body Combat
BIO:Biology CBE:Combat Engineer
CHM:Chemistry CMP:Computers
CRM:Combat Rifeman CVE:Civil Engineer
DIS:Disguise ELC:Electronics ... ...`

edited Jul 22 '14 at 00:27

answered Jul 22 '14 at 00:12

masat

350
1
10

I get this error when I try your method on my list of strings :
`Traceback (most recent call last): File "tars.py", line 45, in print fmtcols(jobs,3) File "tars.py", line 10, in fmtcols maxwidth = max(map(lambda x: len(x), mylist)) File "tars.py", line 10, in maxwidth = max(map(lambda x: len(x), mylist)) TypeError: object of type 'int' has no len()` – YouHaveaBigEgo Aug 09 '16 at 00:17

score 0 · Answer 5 · answered Oct 05 '08 at 08:22

0

data = [ ("1","2"),("3","4") ]
print "\n".join(map("\t".join,data))

Not as flexible as the ActiveState solution, but shorter :-)

answered Oct 05 '08 at 08:22

Douglas Leeder

49,001
8
86
133

This doesn't solve the problem, just inserting tab characters will cause the columns to be disjointed when the contents are varying widths (as in the OP's example of 'bad' output) – sidewinderguy Nov 19 '14 at 21:34
1

@sidewinderguy but it is short :-) – Douglas Leeder Nov 20 '14 at 09:19
1

Indeed it is awesomely short :) – sidewinderguy Nov 22 '14 at 02:09

score 0 · Answer 6 · answered Oct 06 '08 at 11:21

The format_columns function should do what you want:

from __future__ import generators
try: import itertools
except ImportError: mymap, myzip= map, zip
else: mymap, myzip= itertools.imap, itertools.izip

def format_columns(string_list, columns, separator=" "):
    "Produce equal-width columns from string_list"
    sublists= []

    # empty_str based on item 0 of string_list
    try:
        empty_str= type(string_list[0])()
    except IndexError: # string_list is empty
        return

    # create a sublist for every column
    for column in xrange(columns):
            sublists.append(string_list[column::columns])

    # find maximum length of a column
    max_sublist_len= max(mymap(len, sublists))

    # make all columns same length
    for sublist in sublists:
         if len(sublist) < max_sublist_len:
             sublist.append(empty_str)

    # calculate a format string for the output lines
    format_str= separator.join(
        "%%-%ds" % max(mymap(len, sublist))
         for sublist in sublists)

    for line_items in myzip(*sublists):
        yield format_str % line_items

if __name__ == "__main__":
    skills_defs = ["ACM:Aircraft Mechanic", "BC:Body Combat", "BIO:Biology",
        "CBE:Combat Engineer", "CHM:Chemistry", "CMP:Computers",
        "CRM:Combat Rifeman", "CVE:Civil Engineer", "DIS:Disguise",
        "ELC:Electronics","EQ:Equestrian", "FO:Forward Observer",
        "FOR:Forage", "FRG:Forgery", "FRM:Farming", "FSH:Fishing",
        "GEO:Geology", "GS:Gunsmith", "HW:Heavy Weapons", "IF:Indirect Fire",
        "INS:Instruction", "INT:Interrogation", "JP:Jet Pilot", "LB:Longbow",
        "LAP:Light Aircraft Pilot", "LCG:Large Caliber Gun", "LNG:Language",
        "LP:Lockpick", "MC:Melee Combat", "MCY:Motorcycle", "MEC:Mechanic",
        "MED:Medical", "MET:Meterology", "MNE:Mining Engineer",
        "MTL:Metallurgy", "MTN:Mountaineering", "NWH:Nuclear Warhead",
        "PAR:Parachute", "PST:Pistol", "RCN:Recon", "RWP:Rotary Wing Pilot",
        "SBH:Small Boat Handling","SCD:Scuba Diving", "SCR:Scrounging",
        "SWM:Swimming", "TW:Thrown Weapon", "TVD:Tracked Vehicle Driver",
        "WVD:Wheeled Vehicle Driver"]

    for line in format_columns(skills_defs, 2):
        print line

This assumes that you have a Python with generators available.

sidewinderguy · Answer 7 · 2014-11-19T21:37:03.373

I think many of these solutions are conflating two separate things into one.

You want to:

be able to force a string to be a certain width
print a table

Here's a really simple take on how to do this:

import sys

skills_defs = ["ACM:Aircraft Mechanic", "BC:Body Combat", "BIO:Biology",
"CBE:Combat Engineer", "CHM:Chemistry", "CMP:Computers",
"CRM:Combat Rifeman", "CVE:Civil Engineer", "DIS:Disguise",
"ELC:Electronics","EQ:Equestrian", "FO:Forward Observer",
"FOR:Forage", "FRG:Forgery", "FRM:Farming", "FSH:Fishing",
"GEO:Geology", "GS:Gunsmith", "HW:Heavy Weapons", "IF:Indirect Fire",
"INS:Instruction", "INT:Interrogation", "JP:Jet Pilot", "LB:Longbow",
"LAP:Light Aircraft Pilot", "LCG:Large Caliber Gun", "LNG:Language",
"LP:Lockpick", "MC:Melee Combat", "MCY:Motorcycle", "MEC:Mechanic",
"MED:Medical", "MET:Meterology", "MNE:Mining Engineer",
"MTL:Metallurgy", "MTN:Mountaineering", "NWH:Nuclear Warhead",
"PAR:Parachute", "PST:Pistol", "RCN:Recon", "RWP:Rotary Wing Pilot",
"SBH:Small Boat Handling","SCD:Scuba Diving", "SCR:Scrounging",
"SWM:Swimming", "TW:Thrown Weapon", "TVD:Tracked Vehicle Driver",
"WVD:Wheeled Vehicle Driver"]

# The only thing "colform" does is return a modified version of "txt" that is
# ensured to be exactly "width" characters long. It truncates or adds spaces
# on the end as needed.
def colform(txt, width):
    if len(txt) > width:
        txt = txt[:width]
    elif len(txt) < width:
        txt = txt + (" " * (width - len(txt)))
    return txt

# Now that you have colform you can use it to print out columns any way you wish.
# Here's one brain-dead way to print in two columns:
for i in xrange(len(skills_defs)):
    sys.stdout.write(colform(skills_defs[i], 30))
    if i % 2 == 1:
        sys.stdout.write('\n')

score 0 · Answer 8 · answered Jun 21 '20 at 06:27

0

This might also help you.

for i in skills_defs:
if skills_defs.index(i)%2 ==0:
    print(i.ljust(30),end = " ")
else:
    print(i.ljust(30))

answered Jun 21 '20 at 06:27

Ayush Jain

144
1
7

Formatting a list of text into columns

8 Answers8

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