Skip to content
/ fmt Public

Using f-strings(PEP 498) style literal string interpolation without Python 3.6.

License

Notifications You must be signed in to change notification settings

damnever/fmt

Folders and files

NameName
Last commit message
Last commit date

Latest commit

29c8b49 · Jan 19, 2017

History

54 Commits
Jan 19, 2017
Jan 19, 2017
Sep 28, 2016
Sep 27, 2016
Sep 25, 2016
Nov 26, 2016
Oct 28, 2016
Sep 25, 2016
Sep 28, 2016

Repository files navigation

f-strings(Python 3.6) style literal string interpolation.

https://img.shields.io/travis/damnever/fmt.svg?style=flat-square https://img.shields.io/pypi/v/fmt.svg?style=flat-square

Using f-strings(PEP 498) style literal string interpolation without Python 3.6.

Usages

  • Accessing the globals and locals.

    import os
    import fmt as f
    
    g_foo = 'global-foo'
    g_bar = 'global-bar'
    g_num = 23
    g_ls = [1, 2, 3]
    
    def scope():
        l_foo = 'local-foo'
        l_bar = 'local-bar'
        print( f('{l_foo}, {l_bar}') )    # 'local-foo, local-bar'
        print( f('{g_foo}, {g_bar!r}') )  # "global-foo, 'global-bar'"
    
    scope()
    print( f('{{ }}') )                   # '{ }'
    print( f('hex: {g_num:#x}') )         # '0x17'
    print( f('{os.EX_OK}') )              # '0'
    print( f('{g_ls[0]}, {g_ls[1]}, {g_ls[2]}') )  # '1, 2, 3'
  • NOTE: Closure will be a little tricky, must pass the outside scope variables as arguments to f, which added a reference to inside the closure in order this can work.

    import fmt as f
    
    def outer(x='xx'):
        y = 'yy'
        def inner():
            print( f('{x}, {y}', x, y) )  # "xx, yy"
        return inner
    
    outer()()
  • Expression evaluation.

    from datetime import datetime
    import fmt as f
    
    class S(object):
        def __str__(self):
            return 'hello'
        def __repr__(self):
            return 'hi'
        def __format__(self, fmt):
            return 'abcdefg'[int(fmt)]
    
    print( f('{1234567890:,}') )             # '1,234,567,890'
    print( f('{1 + 2}') )                    # '3'
    print( f('{str(1 + 2)!r}') )             # "'3'"
    print( f('{[i for i in range(5)]}') )    # '[0, 1, 2, 3, 4]'
    ls = range(5)
    print( f('{{i for i in ls}}') )          # 'set([0, 1, 2, 3, 4])' or '{0, 1, 2, 3, 4}'
    print( f('{{k:v for k,v in zip(range(3), range(3, 6))}}') )  # '{0: 3, 1: 4, 2: 5}'
    print( f('{datetime(1994, 11, 6):%Y-%m-%d}') )               # '1994-11-06'
    print( f('{list(map(lambda x: x+1, range(3)))}') )           # '[1, 2, 3]'
    print( f('{S()!s}, {S()!r}, {S():1}') )                      # 'hello, hi, b'
  • Also, you can register some namespaces for convenience.

    import fmt as f
    
    f.mregister({'x': 1, 'y': 2})  # register multiple
    f.register('z', 3)             # register only one
    
    def func(x, y):
        return x + y
    
    print( f('{func(x, y)}') )  # '3'
    print( f('{func(x, z)}') )  # '4'
    print( f('{func(y, z)}') )  # '5'
  • NOTE: locals() maybe cover the globals(), globals() maybe cover the namespaces that you registered.

Installation

Install by pip:

[sudo] pip install fmt -U

LICENSE

The BSD 3-Clause License