当我的if语句为true时，为什么运行else语句

Question

这是while循环中的一段代码。当我运行这部分代码时，else语句总是打印出来：

for i in range(len(StudentRoster)):
if StudentRoster[i][0] == delInfo[0]:
if StudentRoster[i][1] == delInfo[1]:
del StudentRoster[i]
print(StudentRoster)
else:
print("Student is not already added to the grading manager.")

整个代码：

def GradeManager():
StudentRoster = []
while True:
command = input("$ ")
if command[0:10] == "AddStudent":
AddInput = command[11:]
AddInput = AddInput.replace(" ", "")
StudentInfo = AddInput.split(",")
student = (StudentInfo[0], StudentInfo[1], StudentInfo[2], StudentInfo[3])
StudentRoster.append(student)
print (StudentRoster)
elif command[0:13] == "DeleteStudent":
print("yes")
delStudent = command[14:]
delStudent = delStudent.replace(" ", "")
delInfo = delStudent.split(",")
print (delInfo)
for i in range(len(StudentRoster)):
if StudentRoster[i][0] == delInfo[0]:
if StudentRoster[i][1] == delInfo[1]:
del StudentRoster[i]
print (StudentRoster)
else:
print("Student is not already added to the grading manager.")
else:
print("Fail")
GradeManager()

这是我输入的输入：

$ AddStudent John, Doe, 78, 94
$ AddStudent Jean, Davis, 83, 76
$ AddStudent Aaron, Johnson, 67, 72
$ DeleteStudent Aaron, Johnson

在DeleteStudent之后，即使Aaron Johnson在学生列表上，它也会打印出else语句。

Answer 1

在一次for循环迭代中，if StudentRoster[i][0] == delInfo[0]:的失败