问"for I in range ()“中的"i”是什么意思？

EN

names = ['janet', ' bob', 'charlie']
for name in names:
    print(name)

# Output: janet bob charlie

grid = [[0, 1, 2], 
        [3, 4, 5], 
        [6, 7, 8]]

for row in grid:
    print(row)

# Outputs:
# [0, 1, 2]
# [3, 4, 5]
# [6, 7, 8]

for row in range(3):
    for col in range(3):
        print(grid[col][row])

# Outputs: 0 3 6 1 4 7 2 5 8
# Prints a single digit at a time going from the first of each array to the last
# Instead of printing out an array at a time