def data_file(filename):
  with open(filename) as f:
    for i in range(25):
      c = f.read(1)
      if not c:
        print "End of file"
        break
      print "Read a character:", c
data_file('data1.txt')

如果希望在一行输出中显示结果:

def data_file(filename):
  output = ''
  with open(filename) as f:
    for i in range(25):
      c = f.read(1)
      output = output + c
      if not c:
        print "End of file"
        break
    print(output)
data_file('data1.txt')

您正在迭代您的文件路径。 您需要使用它的路径打开文件，然后遍历它的内容。 只需使用:

def data_file(filename):
  with open(filename) as f:
    for i in range(25):
      ch = f.read(1)
      if not ch:
        print("No more characters")
        break
      print("Character at ", i, " is: ", ch)

data_file('path/to/file')

您有一些语法/打字错误。 在修复它们之后，这应该会起作用:

def data_file(x):
    file=open(x,"r")
    for char in x:
        char=file.read(25) # 2nd use of char
        if not char:
            break
        print(char)
data_file("submission.csv")

在for循环和file read中使用char将覆盖值，您可能希望更改其中一个或另一个