将元组附加到列表，分配索引

Question

我正在开发一个化学程序，该程序需要所有元素及其相应原子质量单位的列表，大致如下：

Elements = [(H,1),(He,2)...(C,12)]

所有元素及其 AMU 都是从文件中读取的，其中每行都写为“C 12”。我需要从文件中读取信息，将每一行附加到自己的元组中，然后将元组附加到列表中。这是我尝试过但没有成功的一些代码。

class chemistry:
    def readAMU():
        infil = open("AtomAMU.txt", "r")
        line = infil.readline()
        Atoms = list()
        Element = ()
        while line !="":
            line = line.rstrip("\n")
            parts = line.split(" ");
            element = parts[0]
            AMU = parts[1]
            element.append(Element)
            AMU.append(Element)
            Element.append(Atoms)

我走在正确的轨道上吗？如果不是，我如何将两个值附加到一个元组中，分配每个值和索引，然后将其附加到一个列表中？

Answer 1

一个更简单的解决方案是使用 for 循环迭代文件：

elements = []
with open("AtomAMU.txt") as f:
    for line in f:
        name, mass = line.split()
        elements.append((name, int(mass)))

Answer 2

假设这些行仅包含 C 12 等，并用空格分隔：

result = []
for line in open('filename.txt'):
    result.append(line.split())

或者如果您碰巧喜欢列表推导式：

[l.split() for l in open('filename.txt')]

请注意，我假设您不关心它是元组还是列表。如果是这样，只需投射它：

[tuple(l.split()) for l in open('filename.txt')]

编辑：谢谢，史蒂文。

Answer 3

字典将是更好的数据结构。

with open("AtomAMU.txt") as f:
    elements_amu = dict(line.split() for line in f)

像这样使用它：

elements_amu['H']   # gets AMU for H
elements_amu.keys() # list of elements without AMU

Answer 4

你的课程表明你是 Python 新手，所以我将尝试清理它并指出一些事情，而不完全重写它。这里的其他解决方案更清晰，但希望这能帮助您理解一些概念。

class chemistry:
    # Because this is a class method, it will automatically
    # receive a reference to the instance when you call the
    # method. You have to account for that when declaring
    # the method, and the standard name for it is `self`
    def readAMU(self):
        infil = open("AtomAMU.txt", "r")
        line = infil.readline()
        Atoms = list()
        # As Frédéric said, tuples are immutable (which means
        # they can't be changed). This means that an empty tuple
        # can never be added to later in the program. Therefore,
        # you can leave the next line out.
        # Element = ()
        while line !="":
            line = line.rstrip("\n")
            parts = line.split(" ");
            element = parts[0]
            AMU = parts[1]
            # The next several lines indicate that you've got the
            # right idea, but you've got the method calls reversed.
            # If this were to work, you would want to reverse which
            # object's `append()` method was getting called.
            # 
            # Original:
            # element.append(Element)
            # AMU.append(Element)
            # Element.append(Atoms)
            # 
            # Correct:
            Element = (element, AMU)
            Atoms.append(Element)
        # If you don't make sure that `Atoms` is a part of `self`,
        # all of the work will disappear at the end of the method
        # and you won't be able to do anything with it later!
        self.Atoms = Atoms

现在，当您想要加载原子序数时，您可以实例化 Chemistry 类并调用其 readAMU() 方法！

>>> c = chemistry()
>>> c.readAMU()
>>> print c.Atoms

请记住，由于最后一行：self.Atoms = Atoms，Atoms 是 c 实例的一部分。

Answer 5

享受。

elementlist= []
datafile= open("AtomAMU.txt")
for elementdata in datafile:
    elementlist.append(elementdata.split(" "))