x轴向右移动？

Question

x轴向右移动，不确定原因。我使用过plt.xlim(left=0)，但是即使没有负值，分布线仍然来自负值？

代码如下：

plt.figure(figsize = (10,10))

# vals will be used to store the index of all the loan_type that equal 'TR'
vals = []
my_vals = []

for x in range(len(df['LOAN_TYPE'])):
    if (df['LOAN_TYPE'][x] == 'TR' or df['LOAN_TYPE'][x] == 'TOFR') and df['PAY_FREQUENCY'][x] == 'M':
        vals = df['LOAN_TYPE'].index[x]
        my_vals.append(vals)

sns.distplot(df['# Payments Made'][my_vals],bins = 60)
#plt.xticks(np.arange(min(df['# Payments Made'][my_vals]),max(df['# Payments Made'][my_vals])+1,1))
plt.axvline(np.mean(df['# Payments Made'][my_vals]), color="r", linestyle="--");