float参数必须是字符串或数字

Question

I have data like this

xmax [[111.34999999999999], [111.3], [111.2], [111.09999999999999], [111.05], [111.05]]

I want xmax[0]

if i write

print xmax[0]

I have [111.34999999999999]

I would like to have 111.34999999999999

Answer 1

您具有列表列表，因此为了只获取第一个值，您必须：

print xmax[0][0]

Answer 2

Few ideas.

Option 0
This is agnostic of the depth of the nesting.

def first(x):
    try:
        return first(x[0])
    except:
        return x

first(xmax)

111.35

---

Option 1
This assumes one layer of nesting and flattens it. It's not efficient as it gets an entire flattened list just to return the first element.

[x for y in xmax for x in y][0]

111.35

---

Option 2
This also assumes one layer of nesting but is efficient in getting the first element.

from cytoolz import concat

next(concat(xmax))

111.35

Answer 3

You need to index the nested list:

print xmax[0][0]
>>> 111.34999999999999