python操作txt文件中数据教程[1]-使用python读写txt文件

filename = './test/test.txt'
contents = []
DNA_sequence = []

# 打开文本并将所有内容存入contents中
with open(filename, 'r') as f:
    for line in f.readlines():
        contents.append(line)
f.close()

# 对contents中的内容进行遍历
# 并将需要的数据存到list DNA_sequence中
for content in contents:  # 逐行遍历
    p = 0  #
    for bit in content:  # 对每行进行逐字遍历
        if bit == " ":  # 遇到空格时进行处理
            DNA_sequence.append(content[0:p])  # 将content中的0：p字段存入新列表new中，用于写入新的.txt中
            break  # 处理完一行以后跳出当前循环
        else:
            p = p + 1  # 如果bit不是空格，指针加1
# print(DNA_sequence)
"""
['AAACAAGGAACAAACGCACA', 'AAAGGACACAGTGAGAGACG', 'AGCCATTGTCGAGTCCGTTA', 'GTGGTCACTCCTCGCAAATT', 'TTCAACCATACAGGCCTCGT',
'CAAATGTGAGGATTCGGACG', 'CCGTGGTGAACTGGAGCGTT', 'Sum', 'AAAGGACACAGTGAGAGACG', 'AGCCATTGTCGAGTCCGTTA',
'CCACAACGCTCGAAGGCAAG', 'AAGTACAGCGGGCCAATAGC', 'CAAATGTGAGGATTCGGACG', 'GAGAACGTTGAGTGAGCGTG', 'GATGTTAAGTAGAGCAGAGG',
'Sum', 'AAACAAGGAACAAACGCACA', 'AAAGGACACAGTGAGAGACG', 'CCACAACGCTCGAAGGCAAG', 'AAGTACAGCGGGCCAAGATC',
'CTCAGAAGATCTCGATGGCT', 'AGCCATTGTCGAGTCCGTTA', 'TGCCGCAAACTACACACACG', 'Sum']
"""
# 由于list DNA_sequence中有不需要的字符串"Sum",将其从列表中去除
for var in DNA_sequence:
    if var == "Sum":
        DNA_sequence.remove(var)
# print(DNA_sequence)
"""
['AAACAAGGAACAAACGCACA', 'AAAGGACACAGTGAGAGACG', 'AGCCATTGTCGAGTCCGTTA', 'GTGGTCACTCCTCGCAAATT', 'TTCAACCATACAGGCCTCGT',
 'CAAATGTGAGGATTCGGACG', 'CCGTGGTGAACTGGAGCGTT', 'AAAGGACACAGTGAGAGACG', 'AGCCATTGTCGAGTCCGTTA', 'CCACAACGCTCGAAGGCAAG',
  'AAGTACAGCGGGCCAATAGC', 'CAAATGTGAGGATTCGGACG', 'GAGAACGTTGAGTGAGCGTG', 'GATGTTAAGTAGAGCAGAGG', 'AAACAAGGAACAAACGCACA'
  , 'AAAGGACACAGTGAGAGACG', 'CCACAACGCTCGAAGGCAAG', 'AAGTACAGCGGGCCAAGATC', 'CTCAGAAGATCTCGATGGCT',
  'AGCCATTGTCGAGTCCGTTA', 'TGCCGCAAACTACACACACG']
"""

# 以写的方式打开文件，如果文件不存在，就会自动创建，如果存在就会覆盖原文件
file_write_obj = open("./DNAlog.txt", 'w')

# 将DNA_sequence中的数据写入到DNAlog.txt文件中
for var in DNA_sequence:
    file_write_obj.writelines(var)
    file_write_obj.writelines('\n')

file_write_obj.close()