從特殊的字符串格式Python中提取變量

Question

我已經從XML文件中檢索了一個字符串，如下所示：

"[0, 30, -146, 0]$[-143, 30, -3, 0]" #[left, top, right, bottom]

（總是相同的格式）

我正在嘗試提取兩個位置的兩個左值：

left1 = 0
left2 = -143

我該怎么辦？

Answer 1

您可以使用正則表達式：

import re
your_str = "[0, 30, -146, 0]$[-143, 30, -3, 0]" #[left, top, right, bottom]
reg = re.compile("\[(-?\d+),")
list_results = re.findall(reg, your_str)
# ['0', '-143']
# if you always have the same kind of str you can even do
# left1, left2 = map(int, re.findall(reg, your_str))  # map to change from str to int

Answer 2

如果您想嘗試不使用正則表達式

string = "[0, 30, -146, 0]$[-143, 30, -3, 0]"
param = string.split("$") #split your string and get ['[0, 30, -146, 0]', '[-143, 30, -3, 0]']
letf = [] #list of your result

#note that param is a List but 'a' is a String
#if you want to acces to first element with index you need to convert 'a' to as list
for a in param:
    b = eval(a) #in this case'eval()' is used to convert str to list
    letf.append(b[0]) #get the first element of the List

print(letf)