Python 导入文本文件并将字符串转换为浮点数

Question

I have encountered some value error when input txt file into python.

the txt file called "htwt.txt", and contain the below data:

Ht Wt

169.6 71.2

166.8 58.2

157.1 56

181.1 64.5

158.4 53

165.6 52.4

166.7 56.8

156.5 49.2

168.1 55.6

165.3 77.8

When I typed the below code, and value errors are occurred.

import numpy as np

import pandas as pd

import matplotlib.pyplot as plt

import os


import statsmodels.api as sm

from statsmodels.formula.api import ols


os.chdir("/Users/James/Desktop/data/")

data1=np.loadtxt("htwt.txt") 

df1=pd.DataFrame(data1)

ValueError: could not convert string to float: 'Ht'

May I know what should the correct code so that it can be converted to the data frame? thanks.

Answer 1

Pandas read_csv is enough

import pandas as pd
import os
os.chdir("/Users/James/Desktop/data/")

df1 = pd.read_csv("htwt.txt",sep=' ')

Output:

>>> df1
      Ht    Wt
0  169.6  71.2
1  166.8  58.2
2  157.1  56.0
3  181.1  64.5
4  158.4  53.0
5  165.6  52.4
6  166.7  56.8
7  156.5  49.2
8  168.1  55.6
9  165.3  77.8

Checking the types:

>>> df.info()
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 10 entries, 0 to 9
Data columns (total 2 columns):
 #   Column  Non-Null Count  Dtype  
---  ------  --------------  -----  
 0   Ht      10 non-null     float64
 1   Wt      10 non-null     float64
dtypes: float64(2)
memory usage: 288.0 bytes

Answer 2

Like mentioned above pandas read_csv works, but if you insist on using np.loadtxt you can skip the first row which can't be converted to a float. You can do:

data1 = np.loadtxt("htwt.txt", skiprows=1)

Answer 3

The first row in your text file has alphanumeric characters: "Ht Wt". These characters cannot be converted to a floating point number. Remove the first row and you should be fine.

Answer 4

#for skipping of the first line file1 = open("hwwt.txt") lines = file1.readlines()[1:] for line in lines: print(line.rstrip()) OUTPUT #otherwise you can use read_csv which is enough