user1107049 - 1 month ago 8
Python Question

# How to convert MB to GB with precision in Python

What would be the fastest way to covert the values given in MB and KB to GB and TB?

``````sizes = ['999.992 MB', '2.488 GB', '401 KB']
``````

sizes_in_GB = ['?', '?', '?']

sizes_in_TB = ['?', '?', '?']

Given:

``````>>> sizes = ['999.992 MB', '2.488 GB', '401 KB']
``````

First agree on what 'precision' means. Since your input is a float, it is a fair assumption that 'precision' is limited to the input precision.

To calculate, first convert to base bytes (know though that your actual precision is no better than the input precision):

``````>>> defs={'KB':1024, 'MB':1024*1024, 'GB':1024*1024*1024, 'TB':1024**4}
>>> bytes=[float(lh)*defs[rh] for lh, rh in [e.split() for e in sizes]]
>>> bytes
[1048567611.392, 2671469658.112, 410624.0]
``````

Then convert to magnitude desired:

``````>>> sd='GB'
>>> ['{:0.2} {}'.format(e/defs[sd], sd) for e in bytes]
['0.98 GB', '2.5 GB', '0.00038 GB']
>>> sd='TB'
>>> ['{:0.2} {}'.format(e/defs[sd], sd) for e in bytes]
['1e+03 MB', '2.5e+03 MB', '0.39 MB']
>>> ['{:0.2} {}'.format(e/defs[sd], sd) for e in bytes]
['0.00095 TB', '0.0024 TB', '3.7e-07 TB']
``````