def banner(text, ch='=', length=78):
"""Return a banner line centering the given text.
"text" is the text to show in the banner. None can be given to have
no text.
"ch" (optional, default '=') is the banner line character (can
also be a short string to repeat).
"length" (optional, default 78) is the length of banner to make.
Examples:
>>> banner("Peggy Sue")
'================================= Peggy Sue =================================='
>>> banner("Peggy Sue", ch='-', length=50)
'------------------- Peggy Sue --------------------'
>>> banner("Pretty pretty pretty pretty Peggy Sue", length=40)
'Pretty pretty pretty pretty Peggy Sue'
"""
if text is None:
return ch * length
elif len(text) + 2 + len(ch)*2 > length:
# Not enough space for even one line char (plus space) around text.
return text
else:
remain = length - (len(text) + 2)
prefix_len = remain / 2
suffix_len = remain - prefix_len
if len(ch) == 1:
prefix = ch * prefix_len
suffix = ch * suffix_len
else:
prefix = ch * (prefix_len/len(ch)) + ch[:prefix_len%len(ch)]
suffix = ch * (suffix_len/len(ch)) + ch[:suffix_len%len(ch)]
return prefix + ' ' + text + ' ' + suffix
