Python 3.x-如何获取字符串左列的值

Question

I am trying to write a program that will print the values from the left column of a string.

This is what I have so far:

str = '''Dear Sam:
From Egypt we went to Italy, and then took a trip to Germany, Holland and England.
We enjoyed it all but Rome and London most.
In Berlin we met Mr. John O. Young of Messrs. Tackico & Co., on his way to Vienna.
His address there is 147 upper Zeiss Street, care of Dr. Quincy W. Long.
Friday the 18th, we join C. N. Dazet, Esquire and Mrs. Dazet, and leave at 6:30 A.M. for Paris
on the 'Q. X.' Express and early on the morning on the 25th of June start for home on the S. S. King.
Very sincerely yours,
Signature of writer'''

splitstr = list(str)
while "True" == "True":
    for i in splitstr:
        left_column = splitstr[0:1]
        print(left_column)
        break

The output is:

["D"]

I'm still in the process of figuring it out, but I do know that I need a while loop and possibly a for loop. I know the break will make the program end right after it gets its value; I put it there because the program would just keep on going. But besides that I'm totally stumped.

Answer 1

When you call list(str) you split the string into individual characters. This happens because strings are sequences too.

To split a string into separate lines use the str.splitlines() method :

for line in somestring.splitlines():
    print line[0]  # print first character

To print the first word of each line, use str.split() to spilt on whitespace:

for line in somestring.splitlines():
    print line.split()[0]  # print first word

Or a little more efficiently by splitting only once:

for line in somestring.splitlines():
    print line.split(None, 1)[0]  # print first word

Answer 2

This is easier:

st='''Dear Sam:
From Egypt we went to Italy, and then took a trip to Germany, Holland and England.
We enjoyed it all but Rome and London most.
In Berlin we met Mr. John O. Young of Messrs. Tackico & Co., on his way to Vienna.
His address there is 147 upper Zeiss Street, care of Dr. Quincy W. Long.
Friday the 18th, we join C. N. Dazet, Esquire and Mrs. Dazet, and leave at 6:30 A.M. for Paris
on the 'Q. X.' Express and early on the morning on the 25th of June start for home on the S. S. King.
Very sincerely yours,
Signature of writer'''

print('\n'.join(e.split()[0] for e in st.splitlines()))  # first word...

or:

print('\n'.join(e[0] for e in st.splitlines())) # first letter