Question

从data = ["1,2","3,4"]我尝试创建字符串列表：["1","2","3","4"]

尝试此代码：

comb = []
for x in data:
    for(y in x.split(',')):
        comb.append(y)

返回：

  File "<ipython-input-46-20897dcf51a1>", line 4
    for(y in x.split(',')):
                          ^
SyntaxError: invalid syntax

当x.split(',')返回已解析元素的列表时，在此上下文中它应该是一个有效的for循环？

Answer 1

性能最佳：避免append，extend：只需使用2个扁平循环执行列表理解：

data = ["1,2","3,4"]
data_flat = [x for c in data for x in c.split(",")]

print(data_flat)

结果：

['1', '2', '3', '4']

Answer 2

你有一个额外的paranthesis。尝试

comb = []
for x in data:
    for y in x.split(','):
        comb.append(y)

Answer 3

你真的不需要内循环。

In [1]: data = ["1,2","3,4"]

In [2]: comb=list()

In [3]: for d in data:
   ...:     comb.extend(d.split(","))
   ...:

In [4]: comb
Out[4]: ['1', '2', '3', '4']

Answer 4

你几乎拥有它。你在第一个上有for权利。似乎split之后的parens让你感到困惑，并让你恢复到另一种编程语言，这种语言将问题置于for和if条件之下。通过从for y删除无关的parens，您可以修复它。

In [22]: data = ["1,2","3,4"]
    ...:
    ...: comb = []
    ...:
    ...: for x in data:
    ...:     for y in x.split(','):
    ...:         comb.append(y)
    ...:

In [23]: comb
Out[23]: ['1', '2', '3', '4']

Answer 5

一个班轮：

print([item for sublist in ["1,2","3,4"] for item in sublist.split(',')])

输出：

['1', '2', '3', '4']

但是你的代码绝对没问题。问题是你在for循环中给出了额外的括号：

data = ["1,2","3,4"]

comb = []
for x in data:
    for y in x.split(','): #corrected
        comb.append(y)

print(comb)

从列表列表中创建单个列表

5 个答案: