Python error: "ValueError: cannot switch from manual field specification to automatic field numbering" and I don't know why

Question

I have been working on making a multiplication table using a function, a for loop and string formatting. I tried a small-scale test table going up to twenty, which printed fine. then, I went all the way up to 100, and I got this error: "ValueError: cannot switch from manual field specification to automatic field numbering" and I don't know why. I do have a very large code, and I may have made some spelling mistakes. I realize that there is probably an easier way of doing it, but I am just unaware of it. I don't know advanced Python methods, sadly. Here is the up-to-twenty code which I wrote:

def createtable():
    layout = "{0:>5} {1:>5} {2:>5} {3:>5} {4:>5} {5:>5} {6:>5} {7:>5} {8:>5} {9:>5} {10:>5} {11:>5} {12:>5} {13:>5} {14:>5} {15:>5} {16:>5} {17:>5} {18:>5} {19:>5} {20:>5}"
    print(layout.format(" ","1","2","3","4","5","6","7","8","9","10","11","12","13","14","15","16","17","18","19","20"))
    print("    |------------------------------------------------------------------------------------------------------------------------")
    for i in range(1,21):
        print(layout.format(str(i)+"|",1*i,2*i,3*i,4*i,5*i,6*i,7*i,8*i,9*i,10*i,11*i,12*i,13*i,14*i,15*i,16*i,17*i,18*i,19*i,20*i))

and here is the code that I couldn't get to work:

def createtable2():
    layout = "{0:>5} {1:>5} {2:>5} {3:>5} {4:>5} {5:>5} {6:>5} {7:>5} {8:>5} {9:>5} {10:>5} {11:>5} {12:>5} {13:>5} {14:>5} {15:>5} {16:>5} {17:>5} {18:>5} {19:>5} {20:>5} {21:>5} {22:>5} {23:>5} {24:>5} {25:>5} {26:>5} {27:>5} {28:>5} {29:>5} {30:>5} {31:>5} {32:>5} {34:>5} {35:>5} {36:>5} {37:>5} {38:>5} {39:>5} {40:>5} {41:>5} {42:>5} {:43>5} {44:>5} {45:>5} {46:>5} {47:>5} {48:>5} {49:>5} {50:>5} {51:>5} {52:>5} {53:>5} {54:>5} {55:>5} {56:>5} {57:>5} {58:>5} {59:>5} {60:>5} {61:>5} {62:>5} {63:>5} {64:>5} {65:>5} {66:>5} {67:>5} {68:>5} {69:>5} {70:>5} {71:>5} {72:>5} {73:>5} {74:>5} {75:>5} {76:>5} {77:>5} {78:>5} {79:>5} {80:>5} {81:>5} {82:>5} {83:>5} {84:>5} {85:>5} {86:>5} {87:>5} {89:>5} {90:>5} {91:>5} {92:>5} {93:>5} {94:>5} {95:>5} {96:>5} {97:>5} {98:>5} {99:>5} {100:>5}"
    print(layout.format(" ","1","2","3","4","5","6","7","8","9","10","11","12","13","14","15","16","17","18","19","20","21","22","23","24","25","26","27","28","29","30","31","32","33","34","35","36","37","38","39","40","41","42","43","44","45","46","47","48","49","50","51","52","53","54","55","56","57","58","59","60","61","62","63","64","65","66","67","68","69","70","71","72","73","74","75","76","77","78","79","80","81","82","83","84","85","86","87","88","89","90","91","92","93","94","95","96","97","98","99","100"))
    print("    |------------------------------------------------------------------------------------------------------------------------")
    for i in range(1,21):
        print(layout.format(str(i)+"|",1*i,2*i,3*i,4*i,5*i,6*i,7*i,8*i,9*i,10*i,11*i,12*i,13*i,14*i,15*i,16*i,17*i,18*i,19*i,20*i))

I don't know what is wrong. Could someone please help me?

Answer 1

You made 3 typos in layout:

1. You are missing {33:>5}
2. You are missing {88:>5}
3. You wrote {:43>5} instead of {43:>5}

It is the final typo that gave rise to the error message you see.

This simply goes to show that manually typing in such a long list is a bad idea as you have a high risk of doing something wrong.

Additionally, the length of layout must match the number of arguments you pass to layout.format. Because of this, you would have gotten another error in the for loop, as the number of arguments in the final layout.format is 21, whereas the layout variable has length 101 (without typos).

I would recommend a generalized approach to such a problem instead, removing the risk of passing a wrong number of arguments, and creating typos. See example below:

def create_table(max_row, max_col):
    layout = ' '.join([f'{{{x}:>5}}' for x in range(max_col + 1)])
    fmt = [str(x) for x in range(1, max_col + 1)]
    print(layout.format(" ", *fmt))
    brk = '------' * max_col

    print(f"    |{brk}")
    for i in range(1, max_row + 1):
        cols = [x * i for x in range(1, max_col + 1)]
        print(layout.format(str(i) + "|", *cols))

>>> create_table(max_row=24, max_col=15)

          1     2     3     4     5     6     7     8     9    10    11    12    13    14    15
    |------------------------------------------------------------------------------------------
   1|     1     2     3     4     5     6     7     8     9    10    11    12    13    14    15
   2|     2     4     6     8    10    12    14    16    18    20    22    24    26    28    30
   3|     3     6     9    12    15    18    21    24    27    30    33    36    39    42    45
   4|     4     8    12    16    20    24    28    32    36    40    44    48    52    56    60
   5|     5    10    15    20    25    30    35    40    45    50    55    60    65    70    75
   6|     6    12    18    24    30    36    42    48    54    60    66    72    78    84    90
   7|     7    14    21    28    35    42    49    56    63    70    77    84    91    98   105
   8|     8    16    24    32    40    48    56    64    72    80    88    96   104   112   120
   9|     9    18    27    36    45    54    63    72    81    90    99   108   117   126   135
  10|    10    20    30    40    50    60    70    80    90   100   110   120   130   140   150
  11|    11    22    33    44    55    66    77    88    99   110   121   132   143   154   165
  12|    12    24    36    48    60    72    84    96   108   120   132   144   156   168   180
  13|    13    26    39    52    65    78    91   104   117   130   143   156   169   182   195
  14|    14    28    42    56    70    84    98   112   126   140   154   168   182   196   210
  15|    15    30    45    60    75    90   105   120   135   150   165   180   195   210   225
  16|    16    32    48    64    80    96   112   128   144   160   176   192   208   224   240
  17|    17    34    51    68    85   102   119   136   153   170   187   204   221   238   255
  18|    18    36    54    72    90   108   126   144   162   180   198   216   234   252   270
  19|    19    38    57    76    95   114   133   152   171   190   209   228   247   266   285
  20|    20    40    60    80   100   120   140   160   180   200   220   240   260   280   300
  21|    21    42    63    84   105   126   147   168   189   210   231   252   273   294   315
  22|    22    44    66    88   110   132   154   176   198   220   242   264   286   308   330
  23|    23    46    69    92   115   138   161   184   207   230   253   276   299   322   345
  24|    24    48    72    96   120   144   168   192   216   240   264   288   312   336   360