if not os.path.isfile(file_path_real): logging.error("File does not exist.") return None, None try: tree = etree.parse(file_path_real) # Obtain the root node. root = tree.getroot() except Exception as reason: logging.error(reason) raise for lic in root: for child in lic: if ...
a.extend([4]) # 相当于 a += [4] print(f"a = {a}") print(f"b = {b}") # 输出 a = [1, 2, 3, 4] b = [1, 2, 3, 4] 解决办法:如果有多个变量指向同一个列表,对列表添加元素,最好使用最简单的+号,再赋值。 23. TypeError: 'tuple' object does not support item assignment ...
l[3]表示访问列表的第四个元素 l [1, 2, 3, 40] tup = (1, 2, 3, 4) tup[3] = 40 Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: 'tuple' object does not support item assignment
17.问:我想使用下标访问集合中的第一个元素,运行代码时提示“TypeError: 'set' object does not support indexing”,是因为集合不支持下标吗? 答:是的。Python集合里面的元素是无序的,不能使用下标访问特定位置的元素。 18.问:我想使用切片操作修改列表中的部分元素,运行代码时提示“ValueError: attempt to assign ...
Contrary to what you might expect, the Python subprocess module does not automatically raise an exception on a non-zero exit code. A failing process is typically not something you want your program to pass over silently, so you can pass a check=True argument to run() to raise an exception...
The reason that the sum variable was converted into the float data type and not the integer data type is that if the compiler had converted it into the integer data type, then it would’ve had to remove the fractional part, which would have resulted in data loss. So, Python always conve...
str1 = 'Hello' str1[0] = 'K' Traceback (most recent call last): File "<input>", line 1, in <module> TypeError: 'str' object does not support item assignment 但是字符串有一个replace()的方法,可以改变字符串中的元素,但是以前的字符串不支持原位改变,所以打印出来的字符串是不会变化的😂...
So Python returns a new string to me. 我也可以使用负索引进行切片。 I can also do slicing using negative indices. 例如,如果我键入S,减去3,Python将给出该序列中的最后三个字符,即h、o和n。 So for example, if I type S, minus 3, Python will give me the last three characters in that sequ...
However, Python does not have a character data type, a single character is simply a string with a length of 1. Square brackets can be used to access elements of the string. Example Get the character at position 1 (remember that the first character has the position 0): ...
IndentationError: unindent does not match any outer indentation level错误表明,你使用的缩进方式不一致,有的是 tab 键缩进,有的是空格缩进,改为一致即可。 如果是 IndentationError: unexpected indent 错误, 则 python 编译器是在告诉你"Hi,老兄,你的文件里格式不对了,可能是tab和空格没对齐的问题",所有 python...