Python从lis中删除特定字符串

Question

我想从列表中删除任何包含字母或特殊字符的字符串。你知道吗

test = ["1.0","2.0","3","asdf","1.0f","1f","@#$aa1", "4"]

我想要的结果是一个新的列表。你知道吗

newTest = ["1.0","2.0","3", "4"]

Answer 1

使用try块比使用正则表达式更容易：

newTest = []

for i in test:
    try:
        float(i) # numeric
        newTest.append(i)

    except:
        pass

Answer 2

如果您只想要数字，可以执行以下操作：

def try_parse(s):
  try:
    f = float(s)
    return 1
  except ValueError:
    return 0

test = ["1.0","2.0","3","asdf","1.0f","1f","@#$aa1", "4"]

t2 = [i for i in test if try_parse(i)==1]
print(t2)

给你：

['1.0', '2.0', '3', '4']

如果你想让它们直接浮动：

def try_parse(s):
  try:
    return float(s)
  except ValueError:
    return 'error'

test = ["1.0","2.0","3","asdf","1.0f","1f","@#$aa1", "4"]

t2 = [try_parse(i) for i in test if try_parse(i)!='error']
print(t2)

提供：

[1.0, 2.0, 3.0, 4.0]

Answer 3

您可以使用re.match：

>>> import re
>>> [i for i in test if re.match(r'^[\d.]+$',i)]
['1.0', '2.0', '3', '4']

r'^[\d.]+$'将只匹配长度为1或更多的点和数字的任何组合。你知道吗