是否有一种简单的方法来替换没有任何内容的逗号？

Question

我正在尝试将字符串列表转换为浮点数,但这不能用1,234.56这样的数字来完成.有没有办法使用string.replace()函数删除逗号所以我只有1234.56？string.replace(',','')似乎不起作用.这是我目前的代码:

fileName = (input("Enter the name of a file to count: "))
print()

infile = open(fileName, "r")
line = infile.read()
split = line.split()
for word in split:
    if word >= ".0":
        if word <= "9":
            add = (word.split())
            for num in add:
                  x = float(num)
                  print(x)

这是我得到的错误:

文件"countFile.py",第29行,在main x = float(num)ValueError:无法将字符串转换为float:'3,236.789'

Answer 1

在字符串上,您可以替换任何字符,例如,:

s = "Hi, I'm a string"
s_new = s.replace(",", "")

此外,您对字符串进行的比较可能并不总是按预期方式执行.最好先转换为数值.就像是:

for word in split:
    n = float(word.replace(",", ""))
    # do comparison on n, like
    # if n >= 0: ...

作为提示,请尝试使用以下内容读取文件with:

# ...
with open(fileName, 'r') as f:
    for line in f:
        # this will give you `line` as a string 
        # ending in '\n' (if it there is an endline)
        string_wo_commas = line.replace(",", "")
        # Do more stuff to the string, like cast to float and comparisons...

这是一种更惯用的方式来读取文件并对每一行执行某些操作.