Python：string.replace（“\ n”，“”）如何在函数的内部和外部表现？

Question

我的代码的目的是将字符串datastr放入二维列表matrix。这在Code_v1中完美工作，但是当我将相同的代码放入函数datastr = datastr.replace("\n", " ")不会像在Code_v1中那样替代\n（从一个" "到几个" ";比较Output_v1到Output_v2）。

为什么是这种情况，我该如何解决它？

我已经阅读了许多关于.replace(old, new)的其他问题，但他们都写了string.replace(old, new)而不是string = string.replace(old, new)。

非常感谢您的回答。

P.S.数学不想用matrix。这就是为什么我使用二维列表而不是numpy.matrix。

P.P.S.这是我的第一个问题。如果有人建议如何提高问题的可读性或对我的编码进行任何改进，请告诉我。

Code_v1：

datastr = """08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08 
49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00 
81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65 
52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91 
22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80 
24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50 
32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70 
67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21 
24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72 
21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95 
78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92 
16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57 
86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58 
19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40 
04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66 
88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69 
04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36 
20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16 
20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54 
01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48""" 

datastr = datastr.replace("\n", " ") # Remove all \n from the string 
print(datastr) 

datalist = datastr.split(" ") # Split the string into a new element by " " for the list datalist 

matrix = [[1 for y in range(20)] for x in range(20)] # create 20x20 "matrix" 

print(datalist) 

for y in range(20): # Write data into the "matrix" as integer 
    for x in range(20): 
     matrix[x][y] = int(datalist[y * 20 + x]) 

Output_v1：

C:\Users\i7\AppData\Local\Programs\Python\Python35-32\pythonw.exe C:/Users/i7/Dropbox/Programmieren/Python/test.py 
08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08 49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00 81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65 52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91 22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80 24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50 32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70 67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21 24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72 21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95 78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92 16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57 86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58 19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40 04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66 88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69 04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36 20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16 20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54 01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48 
['08', '02', '22', '97', '38', '15', '00', '40', '00', '75', '04', '05', '07', '78', '52', '12', '50', '77', '91', '08', '49', '49', '99', '40', '17', '81', '18', '57', '60', '87', '17', '40', '98', '43', '69', '48', '04', '56', '62', '00', '81', '49', '31', '73', '55', '79', '14', '29', '93', '71', '40', '67', '53', '88', '30', '03', '49', '13', '36', '65', '52', '70', '95', '23', '04', '60', '11', '42', '69', '24', '68', '56', '01', '32', '56', '71', '37', '02', '36', '91', '22', '31', '16', '71', '51', '67', '63', '89', '41', '92', '36', '54', '22', '40', '40', '28', '66', '33', '13', '80', '24', '47', '32', '60', '99', '03', '45', '02', '44', '75', '33', '53', '78', '36', '84', '20', '35', '17', '12', '50', '32', '98', '81', '28', '64', '23', '67', '10', '26', '38', '40', '67', '59', '54', '70', '66', '18', '38', '64', '70', '67', '26', '20', '68', '02', '62', '12', '20', '95', '63', '94', '39', '63', '08', '40', '91', '66', '49', '94', '21', '24', '55', '58', '05', '66', '73', '99', '26', '97', '17', '78', '78', '96', '83', '14', '88', '34', '89', '63', '72', '21', '36', '23', '09', '75', '00', '76', '44', '20', '45', '35', '14', '00', '61', '33', '97', '34', '31', '33', '95', '78', '17', '53', '28', '22', '75', '31', '67', '15', '94', '03', '80', '04', '62', '16', '14', '09', '53', '56', '92', '16', '39', '05', '42', '96', '35', '31', '47', '55', '58', '88', '24', '00', '17', '54', '24', '36', '29', '85', '57', '86', '56', '00', '48', '35', '71', '89', '07', '05', '44', '44', '37', '44', '60', '21', '58', '51', '54', '17', '58', '19', '80', '81', '68', '05', '94', '47', '69', '28', '73', '92', '13', '86', '52', '17', '77', '04', '89', '55', '40', '04', '52', '08', '83', '97', '35', '99', '16', '07', '97', '57', '32', '16', '26', '26', '79', '33', '27', '98', '66', '88', '36', '68', '87', '57', '62', '20', '72', '03', '46', '33', '67', '46', '55', '12', '32', '63', '93', '53', '69', '04', '42', '16', '73', '38', '25', '39', '11', '24', '94', '72', '18', '08', '46', '29', '32', '40', '62', '76', '36', '20', '69', '36', '41', '72', '30', '23', '88', '34', '62', '99', '69', '82', '67', '59', '85', '74', '04', '36', '16', '20', '73', '35', '29', '78', '31', '90', '01', '74', '31', '49', '71', '48', '86', '81', '16', '23', '57', '05', '54', '01', '70', '54', '71', '83', '51', '54', '69', '16', '92', '33', '48', '61', '43', '52', '01', '89', '19', '67', '48'] 

Process finished with exit code 0 

Code_v2：

#globals 
matrix = 0 
matrix_data = 0 


def create_matrix(): 

    global matrix 
    global matrix_data 

    datastr = """08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08 
    49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00 
    81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65 
    52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91 
    22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80 
    24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50 
    32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70 
    67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21 
    24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72 
    21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95 
    78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92 
    16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57 
    86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58 
    19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40 
    04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66 
    88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69 
    04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36 
    20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16 
    20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54 
    01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48""" 

    datastr = datastr.replace("\n", " ") # Remove all \n from the string 
    print(datastr) 

    datalist = datastr.split(" ") # Split the string into a new element by " " for the list datalist 

    matrix = [[1 for y in range(20)] for x in range(20)] # create 20x20 "matrix" 

    matrix_data = [[1 for y in range(20)] for x in range(20)] 

    print(datalist) 

    for y in range(20): # Write data into the "matrix" as integer 
     for x in range(20): 
      matrix[x][y] = int(datalist[y * 20 + x]) 


create_matrix() 

Output_v2：

C:\Users\i7\AppData\Local\Programs\Python\Python35-32\pythonw.exe C:/Users/i7/Dropbox/Programmieren/Python/test.py 
Traceback (most recent call last): 
08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08  49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00  81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65  52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91  22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80  24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50  32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70  67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21  24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72  21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95  78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92  16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57  86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58  19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40  04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66  88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69  04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36  20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16  20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54  01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48 
    File "C:/Users/i7/Dropbox/Programmieren/Python/test.py", line 51, in <module> 
    create_matrix() 
    File "C:/Users/i7/Dropbox/Programmieren/Python/test.py", line 46, in create_matrix 
matrix[x][y] = int(datalist[y * 20 + x]) 
ValueError: invalid literal for int() with base 10: '' 
['08', '02', '22', '97', '38', '15', '00', '40', '00', '75', '04', '05', '07', '78', '52', '12', '50', '77', '91', '08', '', '', '', '', '49', '49', '99', '40', '17', '81', '18', '57', '60', '87', '17', '40', '98', '43', '69', '48', '04', '56', '62', '00', '', '', '', '', '81', '49', '31', '73', '55', '79', '14', '29', '93', '71', '40', '67', '53', '88', '30', '03', '49', '13', '36', '65', '', '', '', '', '52', '70', '95', '23', '04', '60', '11', '42', '69', '24', '68', '56', '01', '32', '56', '71', '37', '02', '36', '91', '', '', '', '', '22', '31', '16', '71', '51', '67', '63', '89', '41', '92', '36', '54', '22', '40', '40', '28', '66', '33', '13', '80', '', '', '', '', '24', '47', '32', '60', '99', '03', '45', '02', '44', '75', '33', '53', '78', '36', '84', '20', '35', '17', '12', '50', '', '', '', '', '32', '98', '81', '28', '64', '23', '67', '10', '26', '38', '40', '67', '59', '54', '70', '66', '18', '38', '64', '70', '', '', '', '', '67', '26', '20', '68', '02', '62', '12', '20', '95', '63', '94', '39', '63', '08', '40', '91', '66', '49', '94', '21', '', '', '', '', '24', '55', '58', '05', '66', '73', '99', '26', '97', '17', '78', '78', '96', '83', '14', '88', '34', '89', '63', '72', '', '', '', '', '21', '36', '23', '09', '75', '00', '76', '44', '20', '45', '35', '14', '00', '61', '33', '97', '34', '31', '33', '95', '', '', '', '', '78', '17', '53', '28', '22', '75', '31', '67', '15', '94', '03', '80', '04', '62', '16', '14', '09', '53', '56', '92', '', '', '', '', '16', '39', '05', '42', '96', '35', '31', '47', '55', '58', '88', '24', '00', '17', '54', '24', '36', '29', '85', '57', '', '', '', '', '86', '56', '00', '48', '35', '71', '89', '07', '05', '44', '44', '37', '44', '60', '21', '58', '51', '54', '17', '58', '', '', '', '', '19', '80', '81', '68', '05', '94', '47', '69', '28', '73', '92', '13', '86', '52', '17', '77', '04', '89', '55', '40', '', '', '', '', '04', '52', '08', '83', '97', '35', '99', '16', '07', '97', '57', '32', '16', '26', '26', '79', '33', '27', '98', '66', '', '', '', '', '88', '36', '68', '87', '57', '62', '20', '72', '03', '46', '33', '67', '46', '55', '12', '32', '63', '93', '53', '69', '', '', '', '', '04', '42', '16', '73', '38', '25', '39', '11', '24', '94', '72', '18', '08', '46', '29', '32', '40', '62', '76', '36', '', '', '', '', '20', '69', '36', '41', '72', '30', '23', '88', '34', '62', '99', '69', '82', '67', '59', '85', '74', '04', '36', '16', '', '', '', '', '20', '73', '35', '29', '78', '31', '90', '01', '74', '31', '49', '71', '48', '86', '81', '16', '23', '57', '05', '54', '', '', '', '', '01', '70', '54', '71', '83', '51', '54', '69', '16', '92', '33', '48', '61', '43', '52', '01', '89', '19', '67', '48'] 

Process finished with exit code 1 

Answer 1

You 缩进行datastr。在每行的起始的那些空间是显著：

datastr = """08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08 
    49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00 
    81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65 ... """ 
# ^^ spaces here. 

结果的每一行（除了第一个），开始与4米额外的空间。你的\n换行符被替换得很好，但这些额外的空间仍然存在。

拆分与str.split()与没有参数您的字符串，你将不再需要用空格来代替换行之一：

datalist = datastr.split() 

str.split()不带参数（或None作为第一个参数）上分割任意宽度空白，包括换行符。中间是否有一个或多个空白字符无关紧要。