lin中设置列格式的python字符串

Question

我正试图格式化字符串，使两者之间的所有内容都排成一行。

APPLES                           $.99                           214                       
kiwi                             $1.09                           755 

我试着这样做：

fmt = ('{0:30}{1:30}{2:30}'.format(Fruit,price,qty))

我怎样才能让一个专栏排成一行？我读了那些文件，但我很困惑。我原以为{1:30}会使它有30个空格，然后它会打印下一个项目，但它似乎是前一个项目结束处的30个空格。

谢谢

Answer 1

我认为更好的方法是根据内容自动调整列宽

rows = [('apple', '$1.09', '80'), ('truffle', '$58.01', '2')]

lens = []
for col in zip(*rows):
    lens.append(max([len(v) for v in col]))
format = "  ".join(["{:<" + str(l) + "}" for l in lens])
for row in rows:
    print(format.format(*row))

输出：

apple    $1.09   80
truffle  $58.01  2 

演示：https://code.sololearn.com/cttJgVTx55bm/#py

Answer 2

str.format()正在使字段在可用空间内左对齐。使用alignment specifiers更改对齐方式：

'<' Forces the field to be left-aligned within the available space (this is the default for most objects).

'>' Forces the field to be right-aligned within the available space (this is the default for numbers).

'=' Forces the padding to be placed after the sign (if any) but before the digits. This is used for printing fields in the form ‘+000000120’. This alignment option is only valid for numeric types.

'^' Forces the field to be centered within the available space.

下面是一个例子（左右对齐）：

>>> for args in (('apple', '$1.09', '80'), ('truffle', '$58.01', '2')):
...     print '{0:<10} {1:>8} {2:>8}'.format(*args)
...
apple         $1.09       80
truffle      $58.01        2

Answer 3

直到现在，我才意识到Python有一个格式化列的解决方案——我决定研究一下它，以防它出现，因为我已经为另一种没有内置解决方案（Lua）的语言创建了自己的解决方案，而且由于逻辑是通用的，所以我用几个键将它移植到Python中。

知道Python有自己的解决方案，我将考虑将它集成到我当前的解决方案中。

然而，当我创建了一个替代的解决方案时，我将继续在这里发布我的解决方案，这样您就可以看到我的解决方案是多么的友好-我对Python的抱怨之一是一些格式不够直观，比如False、True（老实说，True，错的话，最好先声明，其他的都很奇怪。。。

示例函数显示使用中的Truncate（注意：一些逻辑开销是不必要的，仍然在移动东西-例如if_Truncate。。。等）同时显示格式列系统。。。

这是非常基本的-将制表符转换为空格，计算列的长度，如果有太多则添加空格-如果有太多的文本，则将其切掉（我的另一个解决方案有一个缓冲区，您可以使用该缓冲区或边框使边框字符显示出来，并强制列之间至少有一个空白字符-我还没有机会将其添加到Python变体中），等。。。

它对于调试和输出来说非常棒。。

有几个主要功能。。。String.FormatColumn（[_width，_text]，…），String.FormatSimpleColumn（_width，[_text，…）。。。]，和String.FormatColumnEx（_empty_chars，[_width，_text]，…）。。

String.FormatSimpleColumn只接受一次宽度，并对所有列使用该宽度，只重复文本。。

String.FormatColumn为每列获取宽度和文本。。。

String.FormatColumnEx与FormatColumn相同，只是它允许您指定要使用的字符而不是空格-我通常对索引行使用小数或其他字符。。。。

对于我的Lua实现，我也可以选择修剪正确的空间，但是如果不需要空间的话，我只能使用一个helper函数来修剪。。。我之所以离开它们，是因为如果您设置了列，那么如果您想。。。修剪很简单。。这也意味着您可以简单地链接函数调用以获得完全相同的结果，而不是链接参数。。。无论哪个最适合你。。

##
## Sandbox - All Works, if public, are released under the ACL or Acecool Company License - Josh 'Acecool' Moser
##


##
## Declarations for Globals, CONSTants, ENUMeration, etc..
##

## Define the tab width in terms of how many space-chars are used per tab character - Pi uses 8, Windows uses 4, some use 2, etc..
CONST_TAB_WIDTH                             = 4


##
## String Library - This library only includes Format Column debugging output format system..
##
class String:


    ##
    ##
    ##
    def FormatColumnStripR( _width = 25, _text ='', *_varargs ):
        return String.FormatColumn( _width, _text, *_varargs ).rstrip( )


    ##
    ##
    ##
    def FormatSimpleColumnStripR( _width = 25, *_varargs ):
        return String.FormatSimpleColumn( _width, *_varargs ).rstrip( )


    ##
    ## Helper function which lets you define width for each text, and it repeats it for you so you can repeat text and all columns will be the same width
    ##
    ## Purpose:
    ##          The purpose of the Format Column Helpers is to improve data output, primarily for debugging so output is easier to follow..
    ## Usage:
    ##      String.FormatColumn( 25, 'Text / Key', 15, 'Some Value', 15, 'Another Key', 50, 'Another Value' )
    ##      String.FormatColumn( 25, 'Text / Key', 15, 'Some Value', 15, 'Another Key', 50, 'Another Value' )
    ##      String.FormatColumn( 25, 'Key', 15, 'Some', 15, 'Another', 50, 'Value' )
    ##
    ## Output:
    ##      Text / Key               Some Value     Another Key    Another Value                                     <LINE END>
    ##      Text / Key               Some Value     Another Key    Another Value                                     <LINE END>
    ##      Key                      Some           Another        Value                                             <LINE END>
    ##
    def FormatColumn( _width = 25, _text = '', *_varargs ):
        return String.FormatColumnEx( ' ', _width, _text, *_varargs )


    ##
    ## Helper function which lets you define width for each text, and it repeats it for you so you can repeat text and all columns will be the same width
    ##
    ## Purpose:
    ##          The purpose of the Format Column Helpers is to improve data output, primarily for debugging so output is easier to follow..
    ## Usage:
    ##      String.FormatColumnEx( '.', 25, 'Text / Key', 15, 'Some Value', 15, 'Another Key', 50, 'Another Value' )
    ##      String.FormatColumnEx( ' ', 25, 'Text / Key', 15, 'Some Value', 15, 'Another Key', 50, 'Another Value' )
    ##      String.FormatColumnEx( ' ', 25, 'Key', 15, 'Some', 15, 'Another', 50, 'Value' )
    ##
    ## Output:
    ##      Text / Key...............Some Value.....Another Key....Another Value.....................................<LINE END>
    ##      Text / Key               Some Value     Another Key    Another Value                                     <LINE END>
    ##      Key                      Some           Another        Value                                             <LINE END>
    ##
    def FormatColumnEx( _empty_char = ' ', _width = 25, _text = '', *_varargs ):
        ## Make sure our text is a string
        _text = str( _text )

        ## For each tab used, calculate how many spaces should be used with minimum of 1 and maximum of 4 being the range depending which snap-point is used.. Then strip that tab and add spaces in its place..
        _text = _text.expandtabs( CONST_TAB_WIDTH )

        ## Count how many additional arguments we have
        _count = len( _varargs )

        ## Since our Ex function, this, must use a paired-system, we make sure the rounded division is > 0
        _more = ( round( _count / 2, 0 ) > 0 )

        ## How many repeating chars do we need to create?
        _reps = ( _width - len( _text ) )

        ## Build a string to fill the empty column space with spaces so everything lines up - as long as the right font is used ( where all chars are the same size )
        _empty = _empty_char * _reps

        ## Now we ensure our text is limited to the _width size - data going over is truncated...TernaryFunc( _reps > 0, _empty, _empty )
        ## _data = String.SubStr( _text + ( _empty ), 0, _width )
        ## _data = ( _text + ( _empty ) )[  : _width ]
        _data = String.Truncate( _text + ( _empty ), _width )

        ## If we have more cars
        if ( _more ):
            ## Recursive call by shifting our VarArgs left so they populate _width and _text - then add the result to the data var... This only stops when no more paired options are left...
            _data = _data + String.FormatColumnEx( _empty_char, *_varargs )

        ## Return the data..
        return _data


    ##
    ## Helper function which lets you define width once, and it repeats it for you so you can repeat text and all columns will be the same width
    ##
    ## Purpose:
    ##          The purpose of the Format Column Helpers is to improve data output, primarily for debugging so output is easier to follow..
    ## Usage:
    ##      String.FormatSimpleColumn( 15, 'Text / Key', 'Some Value', 'Another Key', 'Another Value' )
    ##      String.FormatSimpleColumn( 15, 'Key', 'Some', 'Another', 'Value' )
    ##
    ## Output:
    ##      Text / Key     Some Value     Another Key    Another Value  <LINE END>
    ##      Key            Some           Another        Value          <LINE END>
    ##
    def FormatSimpleColumn( _width = 25, *_varargs ):
        ## Count how many text elements we have...
        _count = len( _varargs )

        ## Set up our return var
        _data = ''

        ## If we have at least 1 text element to set-up into a column
        if ( _count > 0 ):
            ## Then we loop through each vararg
            for _text in _varargs:
                ## If width is negative, use the length of the string plus the absolute value of width as a buffer...
                if ( _width < 0 ):
                    _data = _data + String.FormatColumn( len( str( _text ) ) + abs( _width ), str( _text ) )
                else:
                    ## And we use a pseudo recursive call on the FormatColumnEx function - extra args...
                    _data = _data + String.FormatColumn( _width, str( _text ) )

        ## Return the data..
        return _data


    ##
    ## SubString replacement
    ##
    ## Usage:
    ##      _data = String.SubStr( _text, 0, 10 )
    ##
    def SubStr( _text, _start, _end ):
        return _text[ _start : _end ]


    ##
    ## Truncate characters of a string after _len'nth char, if necessary... If _len is less than 0, don't truncate anything... Note: If you attach a suffix, and you enable absolute max length then the suffix length is subtracted from max length... Note: If the suffix length is longer than the output then no suffix is used...
    ##
    ## Usage: Where _text = 'Testing', _width = 4
    ##      _data = String.Truncate( _text, _width )                        == Test
    ##      _data = String.Truncate( _text, _width, '..', True )            == Te..
    ##
    ## Equivalent Alternates: Where _text = 'Testing', _width = 4
    ##      _data = String.SubStr( _text, 0, _width )                       == Test
    ##      _data = _text[  : _width ]                                      == Test
    ##      _data = ( _text )[  : _width ]                                  == Test
    ##
    def Truncate( _text, _max_len = -1, _suffix = False, _absolute_max_len = True ):
        ## Length of the string we are considering for truncation
        _len            = len( _text )

        ## Whether or not we have to truncate
        _truncate       = ( False, True )[ _len > _max_len ]

        ## Note: If we don't need to truncate, there's no point in proceeding...
        if ( not _truncate ):
            return _text

        ## The suffix in string form
        _suffix_str     = ( '',  str( _suffix ) )[ _truncate and _suffix != False ]

        ## The suffix length
        _len_suffix     = len( _suffix_str )

        ## Whether or not we add the suffix
        _add_suffix     = ( False, True )[ _truncate and _suffix != False and _max_len > _len_suffix ]

        ## Suffix Offset
        _suffix_offset = _max_len - _len_suffix
        _suffix_offset  = ( _max_len, _suffix_offset )[ _add_suffix and _absolute_max_len != False and _suffix_offset > 0 ]

        ## The truncate point.... If not necessary, then length of string.. If necessary then the max length with or without subtracting the suffix length... Note: It may be easier ( less logic cost ) to simply add the suffix to the calculated point, then truncate - if point is negative then the suffix will be destroyed anyway.
        ## If we don't need to truncate, then the length is the length of the string.. If we do need to truncate, then the length depends on whether we add the suffix and offset the length of the suffix or not...
        _len_truncate   = ( _len, _max_len )[ _truncate ]
        _len_truncate   = ( _len_truncate, _max_len )[ _len_truncate <= _max_len ]

        ## If we add the suffix, add it... Suffix won't be added if the suffix is the same length as the text being output...
        if ( _add_suffix ):
            _text = _text[ 0 : _suffix_offset ] + _suffix_str + _text[ _suffix_offset: ]

        ## Return the text after truncating...
        return _text[ : _len_truncate ]


    ##
    ##
    ##
    def __example__( self ):
        ##
        ## Truncate Example...
        ##
        _col_key    = 20
        _col_eq     = 10
        _col_res    = 15
        _row_eq     = '=='
        _text       = 'Testing'
        print( '--------------------------------------------- 8' )
        _width = 8
        print( String.FormatColumn( _col_key, 'Testing',        _col_eq, _row_eq,           _col_res, String.Truncate( _text, _width ) ) )
        print( String.FormatColumn( _col_key, 'Testing',        _col_eq, _row_eq,           _col_res, String.Truncate( _text, _width, '..', True ) ) )
        print( '--------------------------------------------- 7' )
        _width = 7
        print( String.FormatColumn( _col_key, 'Testing',        _col_eq, _row_eq,           _col_res, String.Truncate( _text, _width ) ) )
        print( String.FormatColumn( _col_key, 'Testing',        _col_eq, _row_eq,           _col_res, String.Truncate( _text, _width, '..', True ) ) )
        print( '--------------------------------------------- 6' )
        _width = 6
        print( String.FormatColumn( _col_key, 'Testin',         _col_eq, _row_eq,           _col_res, String.Truncate( _text, _width ) ) )
        print( String.FormatColumn( _col_key, 'Test..',         _col_eq, _row_eq,           _col_res, String.Truncate( _text, _width, '..', True ) ) )
        print( '--------------------------------------------- 5' )
        _width = 5
        print( String.FormatColumn( _col_key, 'Testi',          _col_eq, _row_eq,           _col_res, String.Truncate( _text, _width ) ) )
        print( String.FormatColumn( _col_key, 'Tes..',          _col_eq, _row_eq,           _col_res, String.Truncate( _text, _width, '..', True ) ) )
        print( '--------------------------------------------- 4' )
        _width = 4
        print( String.FormatColumn( _col_key, 'Test',           _col_eq, _row_eq,           _col_res, String.Truncate( _text, _width ) ) )
        print( String.FormatColumn( _col_key, 'Te..',           _col_eq, _row_eq,           _col_res, String.Truncate( _text, _width, '..', True ) ) )
        print( '--------------------------------------------- 3' )
        _width = 3
        print( String.FormatColumn( _col_key, 'Tes',            _col_eq, _row_eq,           _col_res, String.Truncate( _text, _width ) ) )
        print( String.FormatColumn( _col_key, 'T..',            _col_eq, _row_eq,           _col_res, String.Truncate( _text, _width, '..', True ) ) )
        print( '--------------------------------------------- 2' )
        _width = 2
        print( String.FormatColumn( _col_key, 'Te',             _col_eq, _row_eq,           _col_res, String.Truncate( _text, _width ) ) )
        print( String.FormatColumn( _col_key, '..',             _col_eq, _row_eq,           _col_res, String.Truncate( _text, _width, '..', True ) ) )
        print( '--------------------------------------------- 1' )
        _width = 1
        print( String.FormatColumn( _col_key, 'T',              _col_eq, _row_eq,           _col_res, String.Truncate( _text, _width ) ) )
        print( String.FormatColumn( _col_key, '.',              _col_eq, _row_eq,           _col_res, String.Truncate( _text, _width, '..', True ) ) )
        print( '--------------------------------------------- 0' )
        _width = 0
        print( String.FormatColumn( _col_key, '',               _col_eq, _row_eq,           _col_res, String.Truncate( _text, _width ) ) )
        print( String.FormatColumn( _col_key, '',               _col_eq, _row_eq,           _col_res, String.Truncate( _text, _width, '..', True ) ) )
        print( '---------------------------------------------' )