数据可视化之导入数据

1.从CSV中导入数据

import csv,sys

filename = 'ch02-data.csv'

data = []
try:
    with open(filename) as f:
        reader = csv.reader(f)
        header = next(reader)
        data = [row for row in reader]
except csv.Error as e:
    print("Error reading CSV file at line %s: %s" % (reader.line_num, e))
    # sys.exit(-1)

if header:
    print(header)
    print('==================')

for datarow in data:
    print(datarow)

注意：python2和python3中next方法以变，python2是reader.next(),python3是next(reader)。

https://www.cnblogs.com/hfdkd/p/7719134.html

工作原理

补充说明

import numpy as np

filename = 'ch02-data.csv'
data = np.loadtxt(filename, dtype='str', delimiter=',')
print(data)

2.从Excel中导入数据

import xlrd  ## 专门读取 excel 的 package

from pprint import pprint

file = r"ch02-xlsxdata.xlsx"
wb = xlrd.open_workbook(filename=file)  # 读取 excel 文件，返回 xlrd.book.Book 类的实例对象
ws = wb.sheet_by_name("Sheet1")  # 根据 sheet name 读取 sheet 中的数据，返回 xlrd.sheet.Sheet 类的实例对象
data_set = []
for r in range(ws.nrows):  # sheet 的行数
    col = []
    for c in range(ws.ncols):  # sheet 的列数
        col.append(ws.cell(r, c).value)  # 获取指定的 Cell 的实例对象，通过  value 属性获取值
    data_set.append(col)
pprint(data_set)
for i in data_set:
    print(i)

工作原理

 注意：python的pprint模块。https://blog.csdn.net/iamaiearner/article/details/9378093

补充说明

使用pandas从Excel中导入数据更加方便

import pandas as pd
import numpy as np

np.set_printoptions(linewidth=2000)
filname = 'ch02-xlsxdata.xlsx'
data = pd.read_excel(filname, header=None)
print(data.values)

pandas读取Excel更多内容https://www.cnblogs.com/xinmomoyan/p/10875792.html