如何从.txt文件中提取浮点值以用于python中的计算？

Question

count = 0
fname = input("Enter file name: ")
fh = open(fname)
for line in fh:
    if line.startswith("X-DSPAM-Confidence:") :
        print(line)
        count = count + 1
print(count)

有一个包含27行的文件，比如X-DSPAM-Confidence:0.xxxxx，我需要从每个行中提取数值以用于计算。你知道吗

Answer 1

只要格式与您描述的完全一致，就可以使用以下代码：

float(line.split(':')[1])

如果文本中的变化比您描述的更多，您可能需要尝试regex。你知道吗

Answer 2

您可以使用str.rfind(':')来获取:的位置，然后执行字符串切片来获取值。你知道吗

count = 0
fname = input("Enter file name: ")
fh = open(fname)
for line in fh:
    if line.startswith("X-DSPAM-Confidence:") :
        print(line)
        value = line[line.rfind(':'):]  # will take the last occurrence of : to slice the line
        print(value)
        count = count + 1
print(count)

Answer 3

尝试使用split(':')：

代码：

count = 0
fname = input("Enter file name: ")
fh = open(fname)
for line in fh:
    if line.startswith("X-DSPAM-Confidence:") :
        print(line)
        value = line.split(':')[-1]  # will split line into 'X-DSPAM-Confidence' and 'value'
        # if you have ',' at the end of the line, simply do this:
        value = value.strip(',')
        value = float(value)
        print(value)
        count = count + 1
print(count)