#!/usr/bin/env python
def safe_float(obj):
'safe version of float()'
try:
retval=float(obj)
except (ValueError,TypeError),diag:
retval=str(diag)
return retval
def main():
'handles all the data processing'
log=open('cardlog.txt','w')
try:
ccfile=open('carddata.txt','r')
except IOError,e:
log.write('no txns this month\n')
log.close()
return
txns=ccfile.readlines()
ccfile.close()
total=0.00
log.write('account log:\n')
for eachTxn in txns:
result=safe_float(eachTxn)
if isinstance(result,float):
total+=result
log.write('data...processed\n')
else:
log.write('ignored: %s' % result)
print '$%.2f (new balance)' % (total)
log.close()
if __name__ == '_main_':
main()
下面是carddate.txt
% cat carddata.txt
# carddata.txt
previous balance
25
debits
21.64
541.24
25
credits
-25
-541.24
finance charge/late fees
7.30
5