Question

我想知道是否有可能在列表列表中获得每个列表的最小值。

import csv
data=[]
file=input ("Enter file name: ")
with open(file,"r") as f:
      reader = csv.reader(f, delimiter=';')
      for row in reader:
      data.append(row)
print(data)

输出：

[['13.25', '12.97', '13.12', '13.47', '13.44', '13.09', '12.86', '12.78', '12.91', '12.93', '12.91', '13.11'], ['12.92', '13.42', '13.58', '13.7', '13.62', '13.7', '13.31', '12.86', '12.59', '12.81', '13.46', '12.9'], ['13.39', '13.5', '13.29', '13.26', '13.38', '13.45', '13.46', '11.95', '', '12.57', '13.22', '12.88'], ['12.48', '13.76', '13.7', '13.77', '13.08', '13.48', '13.25', '12.31', '12.56', '12.56', '12.95', '13.38'], ['12.52', '14.07', '14.46', '14.13', '13.98', '14.07', '13.92', '12.7', '13.01', '12.79', '13', '13.13']]

Answer 1

通过简单调用map即可实现数字列表列表的最小值：

numbers = [[1,3,6], [6,7,2], [0,-4]]
minimum_numbers = map(min, numbers)
print minimum_numbers
# This prints: [1, 2, -4]

这将返回一个列表，其中为{＆＃34;外部列表＆＃34;中的每个元素调用了min。 numbers。

Answer 2

Python有一个min函数，可以在列表上调用以获得最低值。您可以遍历data列表，并在包含的每个列表中调用min()。

for list in data:
    print(min(list))

鉴于你的输出，这将返回：

第三个是空白的，因为数组中有一个空值。

如果要删除空字符串，可以使用filter()

for list in data:
    list = filter(None, list)
    print(min(list))

此输出

另外我注意到所有的值都是浮点数，你也可以在检查最小值之前转换它们，这样你就不会比较字符串。

for list in data:
    list = filter(None, list)
    list = [float(i) for i in list]
    print(min(list))

Answer 3

首先，您需要将每个项目转换为浮点数。当您阅读以下数据时执行此操作：

import csv
data=[]
file=input ("Enter file name: ")
with open(file,"r") as f:
      reader = csv.reader(f, delimiter=';')
      for row in reader:
          data.append([float(x) for x in row if x]) # converts values to floats, ignores empty ones
print(data)

完成后，只需在每个列表上调用min()：

>>> [min(x) for x in data]
[12.78, 12.59, 11.95, 12.31, 12.52]

您可以缩短阅读循环：

>>> with open(file, "r") as f:
...    reader = csv.reader(f, delimiter=";")
...    data = [[float(x) for x in row] for row in reader]

>>> print([min(x) for x in data])

Answer 4

我认为您应该使用Emil Vikström's answer，但由于您可以控制加载代码，因此可以防止不必要的数据存储，只需执行以下操作：

with open(file,"r") as f:
      reader = csv.reader(f, delimiter=';')
      for row in reader:
          data.append(min(map(float, row)))

Answer 5

我会使用地图功能......

listOfLists = [ [2, 3, 1], [5, 7, 8], .... ]

minValues = map(lambda x: min(x), listOfLists)

Result:
minValues = [1, 5, ...]

列表列表中每个列表的最小值

5 个答案: