Question

我试图将字符串附加到.tmp/uploads/函数返回的列表中。

readlines()

否则：打开（文件，＆＃34; w＆＃34;）为f：换行： f.write（线）

当我测试它时，如果名称已经被转储到文件中，它就可以了。但是，当我第二次运行模块时，会删除附加到列表中的数字，而是替换为新数字。

E.G。

如果我输入名称Gerald Tim并且程序在文件中找到该名称，我第一次运行它时会将数字添加到名称中，但是第二次运行它会删除另一个数字，用新输入替换它号。

我希望程序不要删除最后一个数字输入。

Answer 1

我认为你不应该修改你正在迭代的列表。尝试迭代副本并修改原始文件。此外，您实际上并没有将新行写回文件。试试这个：

 number = str(int(input("Number:")))
 input_name = ((input("Lastname:") + (input("Firstname:")))

 file = "TXT.txt"

 # Open file with default mode for reading
 f = open(file)
 lines = f.readlines()
 f.close()  # close the file sooner rather than later.

 # Loop for each line in the file
 for line in list(lines):  # <-- Create a copy to iterate over
     # The name is the values indexed from 0 (first character) to -4 (fourth to last character)
    name = line[0:-4]
    # Check if name has been appended before
    if name == input_name:
      # If value of name is input_name, concentrate the number onto the line
      found = True
      print("\nYour name has been found in the file.\n")
      new_line = line[:-1] + "," + number + "\n"
      lines.remove(line)
      lines.append(new_line)
      # Break the loop
      break
   # Otherwise, continue the loop
   else:
       found = False

 # Overwrite the file with the updated data.
 with open(file, 'w') as myfile:
     myfile.writelines(lines)

readlines方法只提供从文件中读取的行的列表 - 修改它不会修改文件。获得修改后的列表后，覆盖该文件。现在这个号码应该在第二次运行时出现。

希望有所帮助。

Answer 2

有点简洁易读（pythonic）。这将根据您的条件查找名称，并将结果附加到上面脚本中指定的数组中。

number = str(int(input("Number:")))
input_name = ((input("Lastname:") + (input("Firstname:")))

file = "TXT.txt"

# initialize result array
res_array = []

# Open file with default mode for reading
with open(file, 'r') as f:
    for line in f.readlines():
        if input_name == line[0:-4]:
            print("\nYour name has been found in the file")
            res_array.append("{0},{1}".format(line[:-1], number))
            break
        else:
            res_array.append(line)

# print out the resulting array
print(res_array)

如果您需要输出到另一个文件，那么：

number = str（int（input（“Number：”））） input_name =（（input（“Lastname：”）+（input（“Firstname：”）））

file = "TXT.txt"

# output file
outfile = "outTXT.txt"

# Open file with default mode for reading
with open(file, 'r') as f:
    with open(outfile, 'w') as fo:
        for line in f.readlines():
            if input_name == line[0:-4]:
                print("\nYour name has been found in the file")
                fo.write("{0},{1}\n".format(line[:-1], number))
                break
            else:
                fo.write("{0}\n".format(line))

通过 with 关键字，文件将在退出特定缩进后立即关闭。

如何将字符串添加到readlines（）函数创建的列表中

2 个答案: