我前几天面试，遇到了以下问题。虽然我确实解决了它，但我想知道如何改进我的 Python 代码以使其 pythonic 并提高可读性，或者是否有任何我没有检查的边缘情况。任何建议将不胜感激！
编写一个 Python 程序，该程序采用 2 个笛卡尔坐标并以标准形式 (Ax+By=C) 输出一条线。 请注释代码并确保符合 PEP-8(最好使用库)。
我的解决方案：
import re # used to check whether the input is a valid number
import sys # used to read input from command line arguments
def process_input():
"""Process the input from command line arguments
Args:
None
Returns:
list: the return value. Empty list indicates
the number of arguments is not four or all input
are not valid numbers. Non-empty list contains
the valid input numbers.
"""
patternobj = re.compile(r'^-?d+.?d*$') # regex pattern object
if len(sys.argv[1:]) == 4: # input should have four arguments
input = [float(num) for num in sys.argv[1:]
if patternobj.match(num)] # string to float
else: # arguments doesn't have four arguments then return empty list
return []
return input
def standard_form(input: list):
"""Print the line function in standard form
Args:
param1: a list contains the coordinates information
Returns:
string: the return value. The string contains
the line function in standard form or error
message.
"""
if len(input) != 4: # the length of list should be 4 otherwise is invalid
return 'Error: Invalid input format'
[x1, y1, x2, y2] = input
if x1 == x2 == y1 == y2: # edge case 1: two same points
return 'Error: Two equal coordinates'
elif x1 == x2: # edge case 2: the slope is infinite
return 'x=' + str(int(x1) if x1.is_integer() else round(x1, 2))
elif y1 == y2: # edge case 3: the slope is 0
return 'y=' + str(int(y1) if y1.is_integer() else round(y1, 2))
A = y2 - y1 # get the value of A
if A == 1: # if A equals 1
A = '' # should not print 1
elif A == -1: # if A equals -1
A = '-' # should print a minus sign
else:
# to string and if it is integer convert to int
A = str(int(A) if A.is_integer() else round(A, 2))
B = x1 - x2 # get the value of B
if B == 1: # if B equals 1
B = '+' # should not print 1 but add a + sign
elif B == -1: # if B equals -1
B = '-' # should not print -1 but add a - sign
else:
if B > 0: # if B is positive
# to string and if it is integer convert to int
B = '+' + str(int(B) if B.is_integer() else round(B, 2))
else:
# to string and if it is integer convert to int
B = '-' + str(int(-B) if B.is_integer() else round(-B, 2))
C = (x1 - x2) * y1 + (y2 - y1) * x1 # get the value of C
# to string and if is integer convert to int
C = str(int(C) if C.is_integer() else round(C, 2))
return A + 'x' + B + 'y=' + C
def main():
input = process_input()
print(standard_form(input))
if __name__ == '__main__':
main()
为了使用它，您应该键入
python3 line.py 3 4 5 6
输出：
2x-2y=-2
另外，有没有更好的方法来处理争论？上面的方法有效，但我觉得它不是很优雅。
可能应该去代码审查，但我无法控制自己。
正则表达式会使代码难以阅读。为什么不直接try呢？
def process_input():
"""
Process the input from command line arguments
return a list if the input is valid
otherwise return a string indicates the input is invalid
"""
if len(sys.argv[1:]) == 4: # input should have four arguments
try: # Try converting them all to float
input_float = [float(x) for x in sys.argv[1:]]
return input_float # Return floats if successful
except: pass # else just pass to the final return statement
return 'Error: Invalid input format'