在Python中如何将数字转换为浮在混合列表中 [英] in Python how to convert number to float in a mixed list

问题描述

我有一个像这样的字符串列表

I have a list of strings in the form like

a = ['str','5','','4.1']

我想将列表中的所有数字转换为浮点数，但其余部分保持不变

I want to convert all numbers in the list to float, but leave the rest unchanged, like this

a = ['str',5,'',4.1]

我尝试了

map(float,a)

但显然它给了我一个错误，因为某些字符串无法转换为浮点型.我也尝试过

but apparently it gave me an error because some string cannot be converted to float. I also tried

a[:] = [float(x) for x in a if x.isdigit()]

但这只会给我

[5]

，所以浮点数和所有其他字符串都丢失了.我该怎么做才能同时保留字符串和数字?

so the float number and all other strings are lost. What should I do to keep the string and number at the same time?

推荐答案

for i, x in enumerate(a):
    try:
        a[i] = float(x)
    except ValueError:
        pass

这假设您要更改a，要创建新列表，可以使用以下命令:

This assumes you want to change a in place, for creating a new list you can use the following:

new_a = []
for x in a:
    try:
        new_a.append(float(x))
    except ValueError:
        new_a.append(x)

这种try/except方法是标准的 EAFP ，并且还会更多比检查每个字符串是否为有效浮点数更有效，更不易出错.

This try/except approach is standard EAFP and will be more efficient and less error prone than checking to see if each string is a valid float.

这篇关于在Python中如何将数字转换为浮在混合列表中的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！