Python：当我使用findall提取数字时，输出为“ ['39772']”我如何摆脱“ ['']”，以便可以转换为float？

问题描述

我正在使用re.findall（）从文件中的行提取数字，我可以很好地获取数字，但是该函数添加了引号，双引号和方括号，因此我无法转换字符串浮。如何删除数字中的[['']“字符以进行转换？

这是我的代码：

import re
count = 0
total = list()
hand = open('mBox-short.txt')
for line in hand:
    line = line.rstrip()
    x = re.findall('New Revision: ([0-9.]+)',line)
    if len(x) > 0:
        count += 1
        a = str(x)
        total.append(a)
    
print(total)     # test print

total1 = list(map(float,total))          # line 24 -- where I get the ValueError

print(sum(total1)/count)

---

输出：

["['39772']","['39771']","['39770']","['39769']","['39766']","['39765']","['39764']"," 
['39763']","['39762']","['39761']","['39760']","['39759']","['39758']","['39757']"," 
['39756']","['39755']","['39754']","['39753']","['39752']","['39751']","['39750']"," 
['39749']","['39746']","['39745']","['39744']","['39743']","['39742']"]
Traceback (most recent call last):
  File "revisions.py",line 27,in <module>
    total1 = list(map(float,total))
ValueError: Could not convert string to float: ['39772']

---

link to file 'mbox-short.txt'

我正在尝试将数字转换为浮点数，以便可以计算平均值。 我想念什么？在哪里可以找到有关操纵输出格式的信息，以便可以使用它？

谢谢！

解决方法

s = "['123']"

s = s[2:-2] # remove first 2 and last 2 characters

print(float(s))
# 123.0

只需从字符串中删除前两个字符。

,

使用列表推导将total中的所有值转换为浮点数。

total = [float(i.split("'")[1]) for i in total]