Python如何列印出多個變數

我們會在本貼士中來介紹在Python2和3中如何列印出多個變數，或者說如何來構造包含多個變數的字串。

需求

假設你有兩個變數，

city = "Amsterdam"
country = "Netherlands"

請列印出包含這兩個變數city和country的字串，示例如下，

City Amsterdam is in the country Netherlands

解決方案

Python2及3的方法

1. 傳遞引數的值

# Python 2
>>> print "City", city, 'is in the country', country

# Python 3
>>> print("City", city, 'is in the country', country)

2. 格式化字串

格式化字串中，有三種可以傳遞引數的方法，

• 順序傳遞

# Python 2
>>> print "City {} is in the country {}".format(city, country)

# Python 3
>>> print("City {} is in the country {}".format(city, country))

• 建立數字索引

這種方式同上一種方式相比，優點是傳遞引數的時候你可以對引數進行重新排序，而且假如引數被多次引用的話，你只需要在引數列表中輸入一次。

  # Python 2
  >>> print "City {1} is in the country {0}, yes, in {0}".format(country, city)

  # Python 3
  >>> print("City {1} is in the country {0}, yes, in {0}".format(country, city))

• 給每個引用命名

  # Python 2
  >>> print "City {city} is in the country {country}".format(country=country, city=city)

  # Python 3
  >>> print("City {city} is in the country {country}".format(country=country, city=city))

3. 多個引數組成元組來傳遞引數

# Python 2
>>> print "City %s is in the country %s" %(city, country)

# Python 3
>>> print("City %s is in the country %s" %(city, country))

Python3.6+新引入的方法

從Python3.6開始有了新的一種格式化字串的方法-f-strings。 它有點類似於字串格式化方法str.format().

# Only from Python 3.6
>>> print(f"City {city} is in the country {country}".format(country=country, city=city))