Python 3 string format decimal places
Python v2.7 introduced a new string fomatting method, that is now the default in Python3. I started this string formatting cookbook as a quick reference to help me format numbers and strings. Thanks to other contributors I’ve expanded the examples over time. Python 3.6 introduced, formatted string literals, often referred to as f-strings as another method to help format strings.
Jump to the new F-strings section below. The following table shows various ways to format numbers using Python’s str.format(), including examples for both float formatting and integer formatting. To run examples use: To get the output of the first example, formatting a float to two decimal places, you would run: Here are a couple of examples of basic string substitution, the You can also use the numeric position of the variables and change them in the strings, this gives some flexibility when doing the formatting, if you make a mistake in the order you can easily correct without shuffling all the variables
around. 💡 Tip: You can use Prior to python 2.6, the way to format strings tended to be a bit simpler, though limited by the number of arguments it can receive. These methods still work as of Python 3.3, but there are veiled threats of deprecating them completely though no
time table. [PEP-3101] Formatting a floating point number:An example comparing the older
Multiple Substitution ValuesAn example comparing variable substitution:
Not Enough ArgumentsUsing the older format method, I would often get the errors: TypeError: not enough arguments for format string or TypeError: not all arguments converted during string formatting because I miscounted my substitution variables, doing something like the following made it easy to miss a variable. The new Python string formatter you can use numbered parameters so you don’t have to count how many you have, at least on half of it.
More String Formatting with .format()The format() function offers a fair amount of additional features and capabilities, here are a few useful tips and tricks using .format() Named ArgumentsYou can use the string format as a template engine using named arguments, instead of requiring a strict order.
💡 If you are using Python 3.6 or greater, see the f-strings formatting below for an easier way to create template–they also compute faster interpolations! Reuse Same Variable Multiple TimesUsing % to format requires a strict ordering of variables, the
Convert Values to Different BasesA surprising use, you can use the string format command to convert numbers to different bases. Use the letter in the formatter to indicate which number base: decimal, hex, octal, or binary. This example formats the number
Use Format as a FunctionYou can use
Hat tip to earthboundkids who provided this on reddit. Using format as a function can be used to adjust formating by user preference.
InternationalizationTo use locale specific formatting for numbers, you need to first set the locale,
and then use the formating code Here is an example, setting locale and formatting a number to display the proper separator:
Escaping BracesIf you need to use braces when using
Table Formatting DataUse the width and the left and right justification to align your data into a nice table format. Here’s an example to show how to format:
This would output: | Andre Iguodala | 4 | 3 | 7 | | Klay Thompson | 5 | 0 | 21 | | Stephen Curry | 5 | 8 | 36 | | Draymon Green | 9 | 4 | 11 | | Andrew Bogut | 3 | 0 | 2 | F-StringsPython 3.6 introduced formatted string literals–yet another method of formatting strings–referred to as f-strings because you start the string specifying an
Formatted string literals support running functions inside of the brackets
1. Do math with f-strings:
2. Call functions with f-strings;
You can use f-strings using the three different type of quotation marks in Python, single, double, or triple quotes. The following will all output the same:
The one thing you’ll want to be careful is mixing the two formats, if you try to use SyntaxError: f-string: empty expression not allowed Each set of brackets used in an f-string requires a value or variable. Resources
How do you format to 3 decimal places in Python?Use the round() function to round a float to 3 decimal places, e.g. result = round(6.36789, 3) . The round() function will round the floating-point number to 3 decimal places and will return the result.
How do you use .2f in Python?2f is a placeholder for floating point number. So %d is replaced by the first value of the tuple i.e 12 and %. 2f is replaced by second value i.e 150.87612 .
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Python String Formatting.. What is .2f in Python 3?As expected, the floating point number (1.9876) was rounded up to two decimal places – 1.99. So %. 2f means to round up to two decimal places. You can play around with the code to see what happens as you change the number in the formatter.
How do you specify 2 decimal places in Python?In Python, to print 2 decimal places we will use str.format() with “{:.2f}” as string and float as a number. Call print and it will print the float with 2 decimal places.
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