如何在Python中用空格将字符串填充到固定长度？
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How to pad a string to a fixed length with spaces in Python?
提问by user2977230
I'm sure this is covered in plenty of places, but I don't know the exact name of the action I'm trying to do so I can't really look it up. I've been reading an official Python book for 30 minutes trying to find out how to do this.
我确信这在很多地方都有涉及，但我不知道我正在尝试执行的操作的确切名称，因此我无法真正查找。我已经阅读了 30 分钟的 Python 官方书籍，试图找出如何做到这一点。
Problem: I need to put a string in a certain length "field".
问题：我需要在一定长度的“字段”中放入一个字符串。
For example, if the name field was 15 characters long, and my name was John, I would get "John" followed by 11 spaces to create the 15 character field.
例如，如果姓名字段的长度为 15 个字符，而我的名字是 John，我将得到“John”后跟 11 个空格以创建 15 个字符的字段。
I need this to work for any string put in for the variable "name".
我需要这个来处理为变量“name”输入的任何字符串。
I know it will likely be some form of formatting, but I can't find the exact way to do this. Help would be appreciated.
我知道这可能是某种形式的格式，但我找不到执行此操作的确切方法。帮助将不胜感激。
采纳答案by Games Brainiac
This is super simple with format:
这非常简单format：
>>> a = "John"
>>> "{:<15}".format(a)
'John '
回答by Aswin Murugesh
string = ""
name = raw_input() #The value at the field
length = input() #the length of the field
string += name
string += " "*(length-len(name)) # Add extra spaces
This will add the number of spaces needed, provided the field has length >= the length of the name provided
这将添加所需的空格数，前提是该字段的长度 >= 所提供名称的长度
回答by Matt
First check to see if the string's length needs to be shortened, then add spaces until it is as long as the field length.
首先检查字符串的长度是否需要缩短，然后添加空格直到它与字段长度一样长。
fieldLength = 15
string1 = string1[0:15] # If it needs to be shortened, shorten it
while len(string1) < fieldLength:
rand += " "
回答by Matt
name = "John" // your variable
result = (name+" ")[:15] # this adds 15 spaces to the "name"
# but cuts it at 15 characters
回答by Ismail Badawi
You can use the ljustmethod on strings.
您可以ljust在 strings 上使用该方法。
>>> name = 'John'
>>> name.ljust(15)
'John '
Note that if the name is longer than 15 characters, ljustwon't truncate it. If you want to end up with exactly 15 characters, you can slice the resulting string:
请注意，如果名称超过 15 个字符，ljust则不会截断它。如果您想以 15 个字符结束，您可以对结果字符串进行切片：
>>> name.ljust(15)[:15]
回答by dragon40226
Just whipped this up for my problem, it just adds a space until the length of string is more than the min_length you give it.
只是针对我的问题提出了这个问题，它只是添加了一个空格，直到字符串的长度大于您给它的 min_length 为止。
def format_string(str, min_length):
while len(str) < min_length:
str += " "
return str
