Re: [Tutor] Help - want to display a number with two decimal places
Modulok wrote:
Notice that 'd' in your string substitution means integers, not
floats. Any decimal places will be truncated when using 'd'. For
floats use 'f' instead. You an also specify a precision, such as
'%.2f' shows two decimal places.
However, to make all of your numbers line up nicely, regardless of how
long they are, you need to look into advanced string formatting via
the builtin string method 'format()'. It takes a little practice to
understand and use, but the results are exactly what you want.
str.format only exists from Python 2.6, but in any case, it certainly
isn't true that you "need" to look at format to make numbers line up
nicely. The examples you give can all be written using string interpolation:
print "{0:<18} {1:>18.2f}".format("Country Sales Tax", countrySalesTax)
print "{0:<18} {1:>18.2f}".format("Purchase Price", purchasePrice)
# First prints the first argument (the 0th index) to 'format(),
# left aligned '<', and 18 characters wide, whitespace padded.
# Then prints the second argument, (the 1st index) right aligned,
# also 18 characters wide, but the second argument is specified to
# be a float 'f', that has a precision of 2 decimal places, '.2'.
>>> countrySalesTax = 11.25
>>> purchasePrice = 124577.35
>>> print "%-18s %18.2f" % ("Country Sales Tax", countrySalesTax); \
... print "%-18s %18.2f" % ("Purchase Price", purchasePrice)
Country Sales Tax 11.25
Purchase Price 124577.35
str.format can do some things better than % interpolation, but
formatting strings to a width is not one of them. It's also a matter of
opinion which is more cryptic:
"%-18s %18.2f"
"{0:<18} {1:>18.2f}"
--
Steven
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Re: [Tutor] Help - want to display a number with two decimal places
"Modulok" wrote However, to make all of your numbers line up nicely, regardless of how long they are, you need to look into advanced string formatting via the builtin string method 'format()'. It takes a little practice Or, if your version of Python doesn't support string.format() (pre 2.6?) you can use \t characters to insert tabs and provide a field length value in the format string and use - signs for string alignment. If you need more you can do double formatting where you use an initial format string to create the output values then insert those into the final output string. The new format() method is more powerful in these jinds of situation (although sadly still not as powerful as COBOLs "picture" feature :-( ) So your strings might look like: # First prints the first argument (the 0th index) to 'format(), # left aligned '<', and 18 characters wide, whitespace padded. # Then prints the second argument, (the 1st index) right aligned, # also 18 characters wide, but the second argument is specified to # be a float 'f', that has a precision of 2 decimal places, '.2'. print "%-18.0s\t%18.2f" %() HTH, -- Alan Gauld Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Help - want to display a number with two decimal places
On 3/4/11, lea-par...@bigpond.com wrote:
> Hello
>
> I have created the following code but would like the program to include two
> decimal places in the amounts displayed to the user. How can I add this?
>
> My code:
>
>
> # Ask user to enter purchase price
> purchasePrice = input ('Enter purchase amount and then press the enter key
> $')
>
> # Tax rates
> stateTaxRate = 0.04
> countrySalesTaxRate = 0.02
>
> # Process taxes for purchase price
>
> stateSalesTax = purchasePrice * stateTaxRate
> countrySalesTax = purchasePrice * countrySalesTaxRate
>
> # Process total of taxes
> totalSalesTax = stateSalesTax + countrySalesTax
>
> # Process total sale price
> totalSalePrice = totalSalesTax + purchasePrice
>
> # Display the data
> print '%-18s %9d' % ('Purchase Price',purchasePrice)
> print '%-18s %9d' % ('State Sales Tax',astateSalesTax)
> print '%-18s %9d' % ('Country Sales Tax',countrySalesTax)
> print '%-18s %9d' % ('Total Sales tax',totalSalesTax)
> print '%-18s %9d' % ('Total Sale Price',totalSalePrice)
>
Lea,
Notice that 'd' in your string substitution means integers, not
floats. Any decimal places will be truncated when using 'd'. For
floats use 'f' instead. You an also specify a precision, such as
'%.2f' shows two decimal places.
However, to make all of your numbers line up nicely, regardless of how
long they are, you need to look into advanced string formatting via
the builtin string method 'format()'. It takes a little practice to
understand and use, but the results are exactly what you want.
(See: http://docs.python.org/library/stdtypes.html#str.format)
Here's an example you could put at the bottom of your code to see it in action:
print "{0:<18} {1:>18.2f}".format("Country Sales Tax", countrySalesTax)
print "{0:<18} {1:>18.2f}".format("Purchase Price", purchasePrice)
# First prints the first argument (the 0th index) to 'format(),
# left aligned '<', and 18 characters wide, whitespace padded.
# Then prints the second argument, (the 1st index) right aligned,
# also 18 characters wide, but the second argument is specified to
# be a float 'f', that has a precision of 2 decimal places, '.2'.
-Modulok-
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[Tutor] Help - want to display a number with two decimal places
HelloI have created the following code but would like the program to include two decimal places in the amounts displayed to the user. How can I add this?My code:# Ask user to enter purchase pricepurchasePrice = input ('Enter purchase amount and then press the enter key $')
# Tax ratesstateTaxRate = 0.04countrySalesTaxRate = 0.02
# Process taxes for purchase price
stateSalesTax = purchasePrice * stateTaxRatecountrySalesTax = purchasePrice * countrySalesTaxRate
# Process total of taxestotalSalesTax = stateSalesTax + countrySalesTax
# Process total sale pricetotalSalePrice = totalSalesTax + purchasePrice
# Display the dataprint '%-18s %9d' % ('Purchase Price',purchasePrice)print '%-18s %9d' % ('State Sales Tax',astateSalesTax)print '%-18s %9d' % ('Country Sales Tax',countrySalesTax)print '%-18s %9d' % ('Total Sales tax',totalSalesTax)print '%-18s %9d' % ('Total Sale Price',totalSalePrice)Thank you in advance for your help.Lea___
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