在python中输出字符串格式

Question

I am encountering an error in outputting a formatted string. I am using Python2.6

lat = 23.456
long = 34.129
# I want to output lat and long, both occupying 8 columns in width, right justified and with 2 values beyond the decimal point
site_file = open('test.site','w')
site_file.write('[{:8.2f}{:8.2f}]'.format(lat,long))

I get the following error: ValueError: zero length field name in format

Any ideas on what I am doing wrong?

thanks!

Answer 1

Python 2.6 and earlier require that you specify the index of the formatted values. Here is an example:

'[{} {}]'.format(a, b)    # Python 2.7 and later 
'[{0} {1}]'.format(a, b)  # Python 2.6 and earlier

I do not have a Python 2.6 interpreter handy, but I believe this is the syntax that you need:

site_file.write('[{0:8.2f}{1:8.2f}]'.format(lat,long))