Question

我希望更改登录if语句。当我使用exec

时

def set_value(array, negation=False):
        equal = "!=" if negation else "=="
        for index1, row in enumerate(pattern_map):
            for index2, column in enumerate(row):   
                exec("if array {} column: kar_map[index1][index2]=1".format(equal))

我得到IndexError

Traceback (most recent call last):
File "/home/charlie/Desktop/Projects/Python/karnaugh_map.py", line       234, in <module>
print(kar_map.map_filled)
File "/home/charlie/Desktop/Projects/Python/karnaugh_map.py", line   176, in map_filled
kar_map = self.__class__.filled_map_1(self.__table.count_variable, self.map_pattern, kar_map, variable)
File "/home/charlie/Desktop/Projects/Python/karnaugh_map.py", line 160, in filled_map_1
set_value("")
File "/home/charlie/Desktop/Projects/Python/karnaugh_map.py", line 148, in set_value
exec("if array {} column: kar_map[index1][index2]=1".format(equal))
File "<string>", line 1, in <module>
TypeError: 'Map' object does not support indexing
[Finished in 0.1s with exit code 1]
[cmd: ['/usr/bin/python3.5', '-u', '/home/charlie/Desktop/Projects/Python/karnaugh_map.py']]
[dir: /home/charlie/Desktop/Projects/Python]
[path:    /usr/local/sbin:/usr/local/bin:/usr/bin:/usr/lib/jvm/default/bin:/opt/ope ncascade/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl]

当我不使用exec时，它可以正常工作。

def set_value(array, negation=False):
        for index1, row in enumerate(pattern_map): 
            for index2, column in enumerate(row):   
                if negation:
                    if array != column:
                        kar_map[index1][index2] = 1
                else:
                    if array == column:
                        kar_map[index1][index2] = 1

任何人都知道这个问题是什么？

Answer 1

使用单行if语句时，将if部分放在要运行的代码之后。另外，.format(equal)没有意义。你想要的是什么？如果您要更改等号（=），则应使用.format(equals = equal)并将=更改为{equals}。你应该改变

exec("if array {} column: kar_map[index1][index2]=1".format(equal))

到

exec("kar_map[index1][index2] {equals} 1 if array {} column".format('=' = equal))

在Python中使用exec获取IndexError

1 个答案: