String formatting in Python

Question

I want to do something like String.Format(\"[{0}, {1}, {2}]\", 1, 2, 3) which returns:

[1, 2, 3]

How do I do this in Python?

Answer 1

To print elements sequentially use {} without specifying the index

print('[{},{},{}]'.format(1,2,3))

(works since python 2.7 and python 3.1)

Answer 2

PEP 498 which landed in python 3.6 added literal string interpolation, which is basically a shortened form of format.

You can now do:

f"[{1}, {2}, {3}]"

Common other uses I find useful are:

pi = 3.141592653589793
today = datetime(year=2018, month=2, day=3)

num_2 = 2     # Drop assigned values in
num_3 = "3"   # Call repr(), or it's shortened form !r
padding = 5   # Control prefix padding
precision = 3 #   and precision for printing


f"""[{1},
     {num_2},
     {num_3!r},
     {pi:{padding}.{precision}},
     {today:%B %d, %Y}]"""

Which will produce:

"[1,\n     2,\n     '3',\n      3.14,\n     February 03, 2018]"

Answer 3

Before answering this question please go through couple of articles given below:

Python Official Docs here

Useful article:

• Python String format() - here

Now let's answer this question

Question: I want to do something like:

String.Format("[{0}, {1}, {2}]", 1, 2, 3) which returns:

[1, 2, 3]

How do I do this in Python?

Answer:

Well this is certainly a one-line code answer which is

print("[{0},{1},{2}]".format(1, 2, 3))

When you execute this one-line code a list containing three values as [1, 2, 3] will be printed. I hope this was pretty simple and self-explanatory.

Thanks

Tanu

Answer 4

You have lot of solutions :)

simple way (C-style):

print("[%i, %i, %i]" %(1, 2, 3))

Use str.format()

print("[{0}, {1}, {2}]", 1, 2, 3)

Use str.Template()

s = Template('[$a, $b, $c]')
print(s.substitute(a = 1, b = 2, c = 3))

You can read PEP 3101 -- Advanced String Formatting

Answer 5

If you don't know how many items are in list, this aproach is the most universal

>>> '[{0}]'.format(', '.join([str(i) for i in [1,2,3]]))

'[1, 2, 3]'

It is mouch simplier for list of strings

>>> '[{0}]'.format(', '.join(['a','b','c']))
'[a, b, c]'

Answer 6

Very short answer.

example: print("{:05.2f}".format(2.5163)) returns 02.51

• {} Set here Variable
• : Start Styling
• 0 leading with zeroes, " " leading with whitespaces
• 5 LENGTH OF FULL STRING (Point counts, 00.00 is len 5 not 4)
• .2 two digit after point, with rounding.
• f for floats