Introduction to the method of reading and writing CSV files in Pandas (with code)

This article brings you an introduction to the method of reading and writing CSV files in Pandas (with code). It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

Read csv: use pandas to read

import pandas as pd
import csv
if name == '__main__':

# header=0——表示csv文件的第一行默认为dataframe数据的行名称,
# index_col=0——表示使用第0列作为dataframe的行索引,
# squeeze=True——表示如果文件只包含一列，则返回一个序列。
file_dataframe = pd.read_csv('../datasets/data_new_2/csv_file_name.csv', header=0, index_col=0, squeeze=True)
# 结果：

# When the parameter index_col=False, row index 0 to n is automatically generated

# csv data:

data_1 = []
# 读取行索引一样的数据,保存为list
try:
    # 行索引为i的数据有多行,列为'pre_star'
    data_1.extend(file_dataframe .loc[i]['pre_star'].values.astype(float))
except AttributeError:
    # 行索引为i的数据只有单行,
    data_1.extend([file_dataframe .loc[i]['pre_star']])
# 多行结果

# There is only one row of data with row index i , you cannot use .values ​​for file_dataframe .loc[i]['pre_star'], otherwise an error will be reported:

##Write csv

Use csv writing

stu1 = [lid, k, pre_count_data[k]]
# 打开文件，写模式为追加'a'
out = open('../results/write_file.csv', 'a', newline='')
# 设定写入模式
csv_write = csv.writer(out, dialect='excel')
# 写入具体内容
csv_write.writerow(stu1)

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