问题描述：

我正在使用 Python 计算如果每 7 秒有一个孩子出生，那么 5 年内会有多少个孩子出生。问题出在最后一行。当我在变量的两侧打印文本时，如何让变量工作？

这是我的代码：

currentPop = 312032486
oneYear = 365
hours = 24
minutes = 60
seconds = 60

# seconds in a single day
secondsInDay = hours * minutes * seconds

# seconds in a year
secondsInYear = secondsInDay * oneYear

fiveYears = secondsInYear * 5

#Seconds in 5 years
print fiveYears

# fiveYears in seconds, divided by 7 seconds
births = fiveYears // 7

print "If there was a birth every 7 seconds, there would be: " births "births"

解决方案 1：

打印时使用,分隔字符串和变量：

print("If there was a birth every 7 seconds, there would be: ", births, "births")

,在打印函数中，各个项目之间用一个空格分隔：

>>> print("foo", "bar", "spam")
foo bar spam

或者更好地使用字符串格式：

print("If there was a birth every 7 seconds, there would be: {} births".format(births))

字符串格式化功能更加强大，还允许您执行一些其他操作，例如填充、对齐、宽度、设置精度等。

>>> print("{:d} {:03d} {:>20f}".format(1, 2, 1.1))
1 002             1.100000
  ^^^
  0's padded to 2

演示：

>>> births = 4
>>> print("If there was a birth every 7 seconds, there would be: ", births, "births")
If there was a birth every 7 seconds, there would be:  4 births

# formatting
>>> print("If there was a birth every 7 seconds, there would be: {} births".format(births))
If there was a birth every 7 seconds, there would be: 4 births

解决方案 2：

Python 是一种非常通用的语言。您可以使用不同的方法打印变量。我在下面列出了五种方法。您可以根据自己的方便使用它们。

例子：

a = 1
b = 'ball'

方法 1：

print('I have %d %s' % (a, b))

方法 2：

print('I have', a, b)

方法 3：

print('I have {} {}'.format(a, b))

方法 4：

print('I have ' + str(a) + ' ' + b)

方法 5：

print(f'I have {a} {b}')

输出结果为：

I have 1 ball

解决方案 3：

还有两个

第一个

>>> births = str(5)
>>> print("there are " + births + " births.")
there are 5 births.

添加字符串时，它们会连接起来。

第二个

此外format（Python 2.6 及更新版本）字符串方法可能是标准方法：

>>> births = str(5)
>>>
>>> print("there are {} births.".format(births))
there are 5 births.

此format方法也可以用于列表

>>> format_list = ['five', 'three']
>>> # * unpacks the list:
>>> print("there are {} births and {} deaths".format(*format_list))  
there are five births and three deaths

或词典

>>> format_dictionary = {'births': 'five', 'deaths': 'three'}
>>> # ** unpacks the dictionary
>>> print("there are {births} births, and {deaths} deaths".format(**format_dictionary))
there are five births, and three deaths

编辑：

现在是 2022 年，python3 有 f 字符串。

>>> x = 15
>>> f"there are {x} births"
'there are 15 births'

解决方案 4：

如果你想使用python 3，这非常简单：

print("If there was a birth every 7 second, there would be %d births." % (births))

解决方案 5：

您可以使用f-string或.format()方法

使用 f 字符串

print(f'If there was a birth every 7 seconds, there would be: {births} births')

使用 .format()

print("If there was a birth every 7 seconds, there would be: {births} births".format(births=births))

解决方案 6：

从 python 3.6 开始，您可以使用文字字符串插值。

births = 5.25487
>>> print(f'If there was a birth every 7 seconds, there would be: {births:.2f} births')
If there was a birth every 7 seconds, there would be: 5.25 births

解决方案 7：

您可以使用格式字符串：

print "There are %d births" % (births,)

或者在这个简单的情况下：

print "There are ", births, "births"

解决方案 8：

如果你使用的是 python 3.6 或最新版本，那么 f-string 是最好且最简单的

print(f"{your_varaible_name}")

解决方案 9：

从 Python-3.8 开始，您可以使用带有变量名称打印的 f 字符串！

age = 19
vitality = 17
charisma = 16
name = "Alice"
print(f"{name=}, {age=}, {vitality=}, {charisma=}")
# name='Alice', age=19, vitality=17, charisma=16

• 这里几乎不可能出现命名错误！如果您添加、重命名或删除变量，您的调试打印将保持正确。

• 调试行非常简洁

• 不用担心对齐问题。第 4 个参数是charisma还是vitality？好吧，你不必关心，无论如何它都是正确的。

解决方案 10：

您首先要创建一个变量：例如：D = 1。然后执行此操作，但将字符串替换为您想要的任何内容：

D = 1
print("Here is a number!:",D)

解决方案 11：

在当前的 Python 版本中你必须使用括号，如下所示：

print ("If there was a birth every 7 seconds", X)

解决方案 12：

您可以使用字符串格式化来执行此操作：

print "If there was a birth every 7 seconds, there would be: %d births" % births

或者您可以给出print多个参数，它会自动用空格分隔它们：

print "If there was a birth every 7 seconds, there would be:", births, "births"

解决方案 13：

使用字符串格式

print("If there was a birth every 7 seconds, there would be: {} births".format(births))
 # Will replace "{}" with births

如果你正在做一个玩具项目使用：

print('If there was a birth every 7 seconds, there would be:' births'births) 

或者

print('If there was a birth every 7 seconds, there would be: %d births' %(births))
# Will replace %d with births

解决方案 14：

只需在中间使用 ,（逗号）即可。

请参阅此代码以便更好地理解：

# Weight converter pounds to kg

weight_lbs = input("Enter your weight in pounds: ")

weight_kg = 0.45 * int(weight_lbs)

print("You are ", weight_kg, " kg")

解决方案 15：

我将您的脚本复制并粘贴到 .py 文件中。我使用 Python 2.7.10 按原样运行它，并收到相同的语法错误。我也在 Python 3.5 中尝试了该脚本，并收到以下输出：

File "print_strings_on_same_line.py", line 16
print fiveYears
              ^
SyntaxError: Missing parentheses in call to 'print'

然后，我修改了打印出生人数的最后一行，如下所示：

currentPop = 312032486
oneYear = 365
hours = 24
minutes = 60
seconds = 60

# seconds in a single day
secondsInDay = hours * minutes * seconds

# seconds in a year
secondsInYear = secondsInDay * oneYear

fiveYears = secondsInYear * 5

#Seconds in 5 years
print fiveYears

# fiveYears in seconds, divided by 7 seconds
births = fiveYears // 7

print "If there was a birth every 7 seconds, there would be: " + str(births) + " births"

输出为（Python 2.7.10）：

157680000
If there was a birth every 7 seconds, there would be: 22525714 births

我希望这会有所帮助。

解决方案 16：

稍有不同：使用 Python 3 并在同一行打印几个变量：

print("~~Create new DB:",argv[5],"; with user:",argv[3],"; and Password:",argv[4]," ~~")

解决方案 17：

Python 3 简介

最好使用格式选项

user_name=input("Enter your name : )

points = 10

print ("Hello, {} your point is {} : ".format(user_name,points)

或者将输入声明为字符串并使用

user_name=str(input("Enter your name : ))

points = 10

print("Hello, "+user_name+" your point is " +str(points))

解决方案 18：

如果在字符串和变量之间使用逗号，如下所示：

print "If there was a birth every 7 seconds, there would be: ", births, "births"