# 创建数据集
data = {'C': 20, 'C++': 15, 'Java': 30, 'Python': 35}
courses = list(data.keys())
values = list(data.values())
fig = plt.figure(figsize=(10, 5))
# 创建条形图
plt.bar(courses, values, color='maroon', width=0.4)
plt.xlabel("开设的课程")
plt.ylabel("注册学生人数")
plt.title("不同课程中的注册学生")
plt.show()

# 创建数据集 - 使用数据框并添加距离零点的位置列
data = {'courses': ['C', 'C++', 'Java', 'Python'], 'values': [20, 15, 30, 35], 'pos': [2, 3, 5, 7]}
df = pd.DataFrame(data)
fig = plt.figure(figsize=(10, 5))
# 创建条形图
plt.bar(df['courses'], df['values'], color='maroon', width=0.4)
plt.xlabel("Courses offered")
plt.ylabel("No. of students enrolled")
plt.title("Students enrolled in different courses")
## 将xlim设置为0到最大值加0.5，以显示所有条形图
plt.xlim(0, df.pos.max() + 0.5)
## 访问每个条形图并根据df.pos中的值设置位置
for container in plt.gca().containers:
    for i, child in enumerate(container.get_children()):
        child.set_x(df.pos[i] - 0.2)  ## 0.2是因为你设置了width=0.4
## 调整刻度和刻度标签
plt.xticks(ticks=df.pos, labels=df.courses)
plt.show()

<details>
<summary>英文:</summary>
To do what you are looking for - setting each bar at a specific place in the x-axis, you need to use `set_x()` for each of the bars. You can get this using `container.get_children()` and then move it around.
Note that I have the data as a dataframe and added a column called `pos`. This will define the distance of each bar from x-axis - zero. Plot the bars, then use set_x() to move the bars and `plt.xlim()` and `plt.xticks()` to align the ticks and labels. Hope this is what you are looking for...

[![enter image description here][1]][1]
  [1]: https://i.stack.imgur.com/DJIfE.png
</details>
# 答案2
**得分**: 1
Maybe you just need to *re-order* the keys of your dictionary ?
d = {k: data[k] for k in ["Java", "C++", "Python", "C"]} # <-- 重新排序的`data`
P = [3, 5, 8, 13] # <-- 每个柱状条/刻度的位置
W = 1.5 # <-- 柱状条的宽度
plt.figure(figsize=(7, 4))
plt.bar(P, d.values(), color="maroon", width=W)
plt.xticks(P, d.keys())
plt.xlim(0, max(P) + W)
输出 :
[![点击这里查看图像描述][1]][1]
  [1]: https://i.stack.imgur.com/RTryc.png
<details>
<summary>英文:</summary>
Maybe you just need to *re-order* the keys of your dictionnary ?
    d = {k: data[k] for k in [&quot;Java&quot;, &quot;C++&quot;, &quot;Python&quot;, &quot;C&quot;]} # &lt;-- re-ordered `data`
    P = [3, 5, 8, 13] # &lt;-- positions of each bar/x-tick
    W = 1.5 # &lt;-- width of the bars
    
    plt.figure(figsize=(7, 4))
    
    plt.bar(P, d.values(), color=&quot;maroon&quot;, width=W)
    
    plt.xticks(P, d.keys())
    plt.xlim(0, max(P) + W)
Output :
[![enter image description here][1]][1]
  [1]: https://i.stack.imgur.com/RTryc.png
</details>