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Super Kai (Kazuya Ito)
Super Kai (Kazuya Ito)

Posted on • Edited on

format_map in Python (1)

#python #formatmap #string #function

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*Memo:

format_map() can create a string with a dictionary, then format the string as shown below:

*Memo:

  • The 1st argument is mapping(Required-Type:Mapping):
    • Don't use mapping=.

<{key}>:

*Memo:

  • A {key} can output a value with no limit.
  • {key} doesn't accept any spaces.
  • {} cannot be used. 
v = {'name':'John', 'age':36} print('- {name} - {age} -'.format_map(v)) # - John - 36 -  print('- {name} - {age} - {name} - {age} -'.format_map(v)) # - John - 36 - John - 36 -  print('{ name }'.format_map(v)) # KeyError: ' name '  print('{ age }'.format_map(v)) # KeyError: ' age '  print('- {} - {} '.format_map(v)) # ValueError: Format string contains positional fields
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*Format Specification can be used with format_map():

v = {'k':-0.0} print('"{k:0>-z#010_.0f}"'.format_map(v)) print('"{k:0>-z#10_.0f}"'.format_map(v)) print('"{k:>-z#010_.0f}"'.format_map(v)) # "000000000."  print('"{k:0>-z#010_.0f}" "{k:0>-z#10_.0f}" "{k:>-z#010_.0f}"'.format_map(v)) # "000000000." "000000000." "000000000."
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<key[key]>:

*Memo:

  • key cannot have "" or ''. 
v = {'name':{'fname':'John', 'lname':'Smith'}} print('- {name}\n- {name[fname]} - {name[lname]} -'.format_map(v)) # - {'fname': 'John', 'lname': 'Smith'} # - John - Smith -  print('{name["fname"]}'.format_map(v)) # KeyError: '"fname"'  print("{name['lname']}".format_map(v)) # KeyError: "'lname'"
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v1 = {'person':{'name':{'fname':'John', 'lname':'Smith'}}} v2 = '- {person}\n- {person[name]}\n\ - {person[name][fname]} - {person[name][lname]} -' print(v2.format_map(v1)) # - {'name': {'fname': 'John', 'lname': 'Smith'}} # - {'fname': 'John', 'lname': 'Smith'} # - John - Smith -
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<key[index]>: 

v = {'name':['John', 'Smith']} print('- {name}\n- {name[0]} - {name[1]} -'.format_map(v)) # - ['John', 'Smith'] # - John - Smith -
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v1 = {'name':[['John', 'Smith']]} v2 = '- {name}\n- {name[0]}\n- {name[0][0]} - {name[0][1]} -' print(v2.format_map(v1)) # - [['John', 'Smith']] # - ['John', 'Smith'] # - John - Smith -
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<key.key>:

*Memo:

  • key cannot be called with (). 
import math v = {'m':math} print('{m.pi}'.format_map(v)) # 3.141592653589793  print('{m.pow}'.format_map(v)) # <built-in function pow>  print('{m.pow(3, 2)}'.format_map(v)) # AttributeError: module 'math' has no attribute 'pow(3, 2)'
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<!s & !r & !a>:

*Memo:

  • !s is str() which can create a string.
  • !r is repr() which can create a printable string.
  • !a is ascii() which can create the printable string of ASCII characters. *Non-ASCII characters are represented with \x, \u, or \U escape. 
v = {"key":"Jφhи\tSмiтh"} print("{key!s}".format_map(v)) # Jφhи Sмiтh  print("{key!r}".format_map(v)) # 'Jφhи\tSмiтh'  print("{key!a}".format_map(v)) # 'J\u03c6h\u0438\tS\u043ci\u0442h'
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v = {'key':'I\'m Jφhи\tSмiтh.'} print('{key!s}'.format_map(v)) # I'm Jφhи Sмiтh.  print('{key!r}'.format_map(v)) # "I'm Jφhи\tSмiтh."  print('{key!a}'.format_map(v)) # "I'm J\u03c6h\u0438\tS\u043ci\u0442h."
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<{{ & }}>

*Memo:

  • { can escape {.
  • } can escape }. 
v = {} print('The bracket {{ is escaped.'.format_map(v)) # The bracket { is escaped.  print('The bracket }} is escaped.'.format_map(v)) # The bracket } is escaped.  print('The {{brackets}} are escaped.'.format_map(v)) # The {brackets} are escaped.
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